Does anybody know what can be the cause?
We won't know the cause - we will just be guessing.
My best guesses...
Are you using the latest build for 24?
Is it happening to just this one file or all files?
Have you followed up those bug reports with your local support people?
They are the best people to talk to about these.
You may be lucky and Minh might see this post and check it out.
But Minh is just one person dealing with everyone in this forum (world-wide), whereas your local support is dealing with just your local area but still has the full resources of Graphisoft to help.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10