Tim Campion and Todd Trimble are currently not listed among the moderators. And their profile pages do not list them as moderators either.

At the same time, I haven't noticed some post on meta related to changes in the moderator team and the answer listing the moderators still shows the same users: History of MathOverflow.

Since the MO users might be wondering about this, I considered that asking on meta might be a reasonable thing to do. Is this just a temporary change? Or will they no longer be moderators?

It goes without saying that if this is related to some reasons which should not be revealed publicly, I am perfectly fine with an answer just stating this (or even with removing this question completely).

Since I saw related post on some other sites, my first guess would be that it is just a technicality - not signing the updated moderator agreement within the given time limit. Or perhaps not logging into the moderator interface for some time - there was one instance of this on MO in the past. (See also: What is the process regarding moderator inactivity removals?)