First of all: The game works totally fine for every official map (official Campaign, TOTD) and every game-mode (solo, live, COTD, ranked etc.).
But when I play a Club Campaign map, like TMWT[e] or any Icy-Campaign (by FlinkTM), I don't have any PB-ghost the next time I play (which means after restarting the game).
My PB-times and world-rankings are saved and displayed correctly (e.g. when I open the stop-watch icon menu). I also can select my PB-ghost via the stop-watch icon menu and drive against it or spectate it - like any other players' ghosts.

But the normal PB-ghost is not available and every features that comes with it:
-- no splits
-- every first run (after game restart) is displayed and announced as a "new best time". So when my actual PB is e.g 00:02.000 and I drive 00:03:000 - congratulations! You got a "new personal best".
-- selecting "drive against opponents (in your region)" gives me 7 other players' ghosts, instead of my PB-ghost plus 3 faster and 3 slower other players' ghosts.

I already posted this problem about a year ago. Since then I have been trying not to be dissappointed at not getting any help. But now I want (or rather have to) learn the TMWT[e] maps in order to play ranked match making properly (because I am ranked "gold" soon). And now I feel dissappointed and helpless again, hence this new post.

@Ubi-Chiral
The problem has been there all the time.
"-:--.---" is shown everytime I start the map.
The exception is when I manage to beat my real PB (meaning: when my PB that is displayed in the stop-watch-menu or "ultimate medal" plugin is updated to a better time/rank) - then everything will be fine: I can exit the map, play another map or mode, and come back to the map, no problems. But I must not RESTART THE GAME, then it is "-:--.---" all over again.
Concerning the medals: they do persist, as do my world-rankings (no harm done there). It is weird. Part of the data is accessed and processed correctly, part is not. I made a series of (new) screenshots to better explain the problems:

@Ubi-TheBerry
I thank YOU for the quick reply.
I stated my disappointment at the beginning of this post. My disappointment mainly originated from not getting any further replies to my previous post a year ago.
If this problem cannot be solved for whatever reasons, please tell me. Of course I'd prefer a solution to this problem, but I will appreciate honesty as well - and I will still love the game.

@Ubi-TheBerry
I did some research - the bug already appeared two years ago:

https://devtrackers.gg/trackmania/p/1c73cadc-pb-times-and-ghosts-disappearing-in-local-play-and-club-campaigns-bug?utm_content=cmp-true: (https://devtrackers.gg/trackmania/p/1c73cadc-pb-times-and-ghosts-disappearing-in-local-play-and-club-campaigns-bug)

@Ubi-MrM
Hello,
Sorry to bother you again, but it is difficult to be patient when doubt arises that one is taken seriously. Or as someone (who knows about this support ticket) put it: 'I think they are playing with you'. Well, I wouldn't want to go as far as that. But am honestly bewildered what could possibly take the investigating team so long to give feedback.
You said the investigation is "ongoing". How should I interpret that statement? Is there a team that has constantly been working on that problem for more than four weeks now? Probably not! That would be a hack of an investment of resources.
Are there certain circumstances that prevent the team from coming up with a solution - a solution that might be found tomorrow, next week, next month - but not now? What could those circumstances be?
I am honestly bewildered and increasingly annoyed. I feel like I am hoping for something that is already decided will never happen. Just tell me if the team cannot solve the problem. This way I can at least bring myself to think: "Well, at least they are being honest." And truely, THAT would be ok with me.