Translation units not adding up to TM in Studio 2017

This is a similar problem to the one I submitted a week or so ago:

Using Studio 2017, in certain projects and with certain TMs, I don’t see the number of translation units adding or changing under Settings of the TM view (neither Project TM nor Main TM).

Yet, the units I’ve confirmed are somewhere in the TM (checked by Concordance Search). This is puzzling me, because it gives me the feeling that the TM is not being populated.

I’ve read somewhere that it would have something to do with Maintenance. But I don’t see concretely what this is and how to solve the problem.

Who can help me find the cause of this problem and solve it?