I think the version loaded by BS.Player's codecmanager is Gabest last "official" version. Apparently you didn't test and try yourself! Version 1.6.3.5588 as referred to by you doesn't solve
makimakimaki's reported issue. In fact it instead adds new problems (see text
below the picture). This new version seems stripped down and simply doesn't cover AAC-audio as you can see from the picture below. (Most probably BS.Player in its default installation uses FFDShow for AAC. I didn't test that now though.) Codecmanager indicates in its info that this filter is an "Alternate audio decoder for AC3/DTS and MPEG audio", which also suggests that BS.Player doesn't use it for any other purposes (such as AAC). So perhaps this issue in fact is only a cosmetical issue which could (?) maybe easily be repaired by slightly shortening
(=moving bottom border up) the window shown for MPA Decoder's properties.
When (easy method: quick and dirty) testing this newer (but non-Gabest!) version, I played several movies and quite a few gave errors, whereas they played without any problems with the "old" MPA Decoder filter. (Also afterwards when I went back to version 1.0.0.4.) So that is IMHO a very good and valid reason to stick to the "old".
(Like I said, my testing was "quick and dirty", so it might just be that this caused the errors.)