Chelsea boss Enzo Maresca was frustrated. Not because of the dismissal of Moises Caicedo against Arsenal on Sunday, but about what he perceived to be a lack of consistency.

You can see his point. Last month Tottenham midfielder Rodrigo Bentancur was booked for a foul on Reece James, which the video assistant referee (VAR) agreed with. Yet when Caicedo was cautioned for a similar challenge on Mikel Merino there was an intervention for a red card.

"It's a red card, but why was Bentancur's against Reece [James] not a red card when we were at Spurs away?" Maresca asked.

"So us, as a manager, we struggle to understand why they judge in a different way.

"Moises' is a red card, yes. Bentancur's is a red card, yes. Why don't they give him a red card? It's just that we struggle to understand. The reality is that it's a red card. But why do they judge it differently?"

So, what was the difference?

Well, outcomes are partly dependent upon who the VAR is - which makes consistency very difficult.

No two fouls are ever the same and there are subtle differences between the two. Bentancur was only really stepping in, while Caicedo jumped a little and his contact point was slightly higher.

There was also a pronounced buckle of Merino's ankle, which is something a VAR is looking for to indicate excessive force, and his boot was shifted back on the turf.

In Bentancur's case, the Premier League's Key Match Incidents (KMI) Panel supported the yellow card for Bentancur by four votes to one, and unanimously backed no VAR intervention "on the basis that the challenge was low, just slightly late and reckless".

The KMI panel will back the decision to send off Caicedo but it will not be too long before another tackle of its type is deemed just a yellow card.

Since the start of the 2023-24 season the KMI Panel has logged 12 errors on serious foul play reviews.

The situation seemed a little confusing at first. Was referee Anthony Taylor being told to book Caicedo so it could be reviewed?

There is a far simpler explanation.

Taylor played advantage to Arsenal as the loose ball was with Eberechi Eze. When it went out for a throw the referee went back to book Caicedo who was down injured needing treatment. Referees are told to wait until an offending player is back on their feet before they show a card.

So, the delay was not because VAR was checking the foul, it was because Caicedo was with the physio.

The VAR will start checking the tackle but there will not be any communication with the referee until he has dished out a card.

In this case, John Brooks as the video referee can reach the conclusion that there is the necessary force for a red, but he has to wait for Taylor to make clear his decision (nothing, yellow or red). As soon as Taylor brandished a yellow, the VAR immediately sent him to the screen because the check had taken place during treatment.

Play restarted with a throw-in only because Taylor played advantage. Had he not done so, it would have been a free-kick. So in a roundabout way, VAR protocol meant Arsenal were penalised for Taylor not getting the red card correct.

Also on Sunday, for only the second time in the Premier League, a referee rejected a red card review at the pitchside monitor.

Chris Kavanagh had not given a foul against Jhon Arias, so unlike for Arsenal the restart was a free-kick to Aston Villa. The VAR, James Bell, felt that the way Arias jumped in with both feet endangered Boubacar Kamara's safety.

Arias was off the floor and took a risk, making contact with the top of Kamara's boot. It did not have the kind of force you need for a red card, even if it was not a great tackle.

A far worse example came last season with Manchester United's Lisandro Martinez, who escaped a red card after a challenge on Crystal Palace's Daichi Kamada.

Martinez jumped in with both feet in the air but was saved by a little known guideline which says a player should not be sent off if the tackle stops before the opponent, and he landed in front of Kamada.

The VAR in the Palace v Manchester United game? Chris Kavanagh.

There was no VAR review to upgrade Martinez's yellow card to a red, which the KMI Panel had to begrudgingly back unanimously, saying it "felt very strongly that this type of challenge has no place on the pitch".

Another weekend, and another set of subjective offside decisions.

Kavanagh was involved again, ruling out a Wolves goal because Arias was offside close to goalkeeper Emiliano Martinez.

There were some similarities to Andrew Robertson's offside a few weeks ago for Liverpool at Manchester City, as both players ducked under the ball - though Arias was a much clearer offence.

But a possible offside on Chelsea's goal appears to have gone under the radar.

James floated a corner in from the left, and Trevoh Chalobah flicked a header into the back of the net.

But there was a problem. Enzo Fernandez was stood in an offside position and was very close to Piero Hincapie and Cristhian Mosquera.

Did Fernandez influence the decision-making of either defender? If the Chelsea midfielder was not there would have been a better chance of stopping the header going in?

Fernandez did not try to play the ball, and while he was not directly engaging with Mosquera he had his arm on Hincapie's back.

You can make a very strong case for offside, so it comes back to a question of consistency again.

It was looked at by the VAR team, who didn't think there was any impact on the defenders.

Perhaps if we hadn't had the decision given against Robertson we wouldn't be talking about offside on this goal.

It was moments after the Caicedo red card. Hincapie jumped for a ball with Chalobah, and the Chelsea defender came off worse through contact by the arm on his face.

"I asked the referee, he said to me that it was not an elbow," Maresca said. "So, this is what they said. [He had a] black eye, with ice at half-time. But they judge in different way."

Referees should not make judgements on a potential injury, though no doubt it happens from time to time. A player can sustain a cut or a bruise from many kinds of challenges and collisions, so it would not make much sense.

As with serious foul play, referees have a checklist they go through when assessing a possible elbow.

Is it an unnatural way of challenging for a high ball? Did the player have a clenched fist, which indicates aggression? Was the elbow thrown or raised to create force? None of these were present, so a yellow card was fine.

Lewis Cook's red card, given by the referee, at Sunderland was a clearer example. While the Bournemouth player didn't have a clenched fist, he raised his elbow to the head of Noah Sadiki.