make me think I did the editing (replacing) texture mentionned in the workaround with the fs-base folder, in order to remove the MMMM and get black back sign, and forgot to actualise the layout.json I don't know if having inconsistency in size file or number may impact performance, but I guess it's worth it doing it, perhaps this should be added to those steps... (maybe this have 0 impact and I may be wrong, if having *.bak file listed in the json could lead to issue, btw kept a save of the initial layout.json)
That's an issue I've noticed too. Unfortunately not even a remote idea for a fix, as even removing the airport files does not help. It hasn't bothered me too much, but can see how it'd be really annoying for some.
I am 99% sure the problem is within the runway textures, included in the Optional Textures, and if that is the case it would need changes done by the developers.