Space access whitelist limits amount of shown folders

We have a quite extensive tree to structure our wiki knowledge and this leads to the problem that in the "Additional filters" section, the whitelist (and most likely the blacklist as well) will not show me all folders available.
Clicking "show me x more" will expand some more folders, but in the end not all are shown.

Even weirder is that the total amount of shown entries seems to be different every time.

If I am searching for my folder with the looking glass it is found, but clicking on it will lead to a "jump" of the page sometimes with this folder being shown, and most of the times not.

We have a proof that there seems to be a limit of shown folders:

If I now create a new page AAA, the last folder shown will bie IT (Internal) in our case.