Here we go again.
Thomas Tuchel has learned a lot about Chelsea since he arrived at the club back in January. He's seen the positives and the negatives, but in Saturday's 5-2 loss to West Brom, he saw the one problem that no manager has been able to solve in the best part of a decade - the mentality issue.
Before Thiago Silva's early red card, Chelsea were uninspiring but in control, but once things turned against them and West Brom started to claw their way back into the game, the Blues disappeared, and Tuchel found that there was nothing he could do to get things back on track.
Where have we heard this one before?
In 2015, after a 2-2 draw with Newcastle, Jose Mourinho said his Chelsea squad didn't have the right attitude to be serial champions.
Three years later, after a 4-1 loss to Watford, Antonio Conte said some in the squad didn't have the personality needed to play for a great club like Chelsea.
Then we had a 2-0 loss to Arsenal in 2019 under Maurizio Sarri, who brutally stated after the game that he simply did not know how to motivate his group of players.
Finally, Frank Lampard finished the cycle after a 3-0 loss to Sheffield United, admitting he had learnt a lot about his team that he would never forget.
You can sack all the managers you want, but Chelsea are five bosses deep into this mentality issue and seemingly no closer to sorting it out. At some point, there has to be an acceptance that the manager isn't the problem.
This isn't to say that the entire squad must be sold. There are some obvious strong links and players who deserve to be part of the future, but there are clearly a handful who looked incredibly out of their depth against 19th-placed West Brom, and they're some of the names that have been touted for exits more than once in the past.
There's no need to overreact to this one defeat, regardless of how disappointing it was. At the end of the day, if you offered Tuchel one loss in his first 15 games at all competitions, he'd definitely have taken it. Things are alright.
Having said that, history shows that this is a lingering problem which won't go away on its own. Four men have lost their jobs to this plague already. Figuring out a solution has left some of the best names in management stumped.
What this result has done is offered Chelsea fans a stark reminder of the reality facing the Blues. They're a great club with some great players, but there is quite clearly something very, very wrong going on.
The sign of true winners is being able to cope with adversity. When things go against you, you need to keep your composure and assert your dominance, but that's not something Chelsea have looked capable of doing for six or seven years now.
However, the Blues have a habit of taking things one step further. Not only do they lose their heads, but they completely capitulate. The ability to play football completely disappears. Had this been a 1-0 loss, it might not have been too bad, but 5-2? 5-2?
We've seen results like this too often in recent years, and regardless of who has been in the dugout, nobody has been able to come up with a solution.
So, Mr Tuchel, can you be the one to figure it out?