Vanishing posts?

Looks like some recent posts just vanished. They still show up in the 'last day' index, but not on the forums themselves? bug or side effect of the server migration? or maybe someone with admin right just doesn't like me :-)

We have not removed any.
The system where the forum runs was upgraded and I know they had some problems with the forum but these were solved.

I hope they did not cause it in the process.