Oversupplu Corrected, but...

[Karl]

Days ago, when I temporarily substituted a bigger aircraft for a smaller one, I got an oversupply notification. I fixed it as soon as I could.

I am still getting this notification:

Game notifications
Route warning
Some of your routes are flying in violation of the game rules (seat oversupply). Please see the message inbox for details.

» Messages

There once was a message, which went away when the oversupply was taken care of.  There is nothing relevant in "messages" anymore.

When will this notification go away?

[Sami]

Did you check the route also from the return leg?

If no problems, it will disappear within a game week.

[Karl]

I finally found it.  The aircraft in question was in C Check.