I am not sure that I can translate correctly everything (I have no English GUI to compare) but here’s the opening post from that forum’s thread:
Hi! The problem is that scan settings aren't saved!
For example, I open "Scan computer - scanning - full scan - more - settings - actions...". There I mark the option "automatically use the chosen action", choose "delete" for all types of files, and click "ОК". I put the search for PUP on too. But when I come back to revise these settings, I see that in all tabs (sometimes in some of them) the automatic actions are changed back to the previous position "no action".
I saw this bug on more than dozen of computers with different versions of Windows.
In the course of the discussion users noticed that the bug appears only if they install Adobe flash player 10.2.152.32 before Avast 6.0.1000. If they install Avast first, there are no bugs with scan settings.