Some setups are susceptible to a random failure when database changes (e.g. local library imports or for playback history tracking) are trying to be saved out. The cause of this is not showing up in the crash reports received so far (also seen with the prior 18916 build) but might be a multi-threading problem.
A possible workaround is to add threads=1 in the [winamp] section of your winamp.ini The location of that can be found by going to Preferences -> Advanced -> Diagnostics -> Settings Locations tab which will show the full path of your winamp.ini file. This change however can make the saving of any db changes much slower which might cause other issues.
The update build button from the about preference page in setups configured to be able to use it will either report a 403 or an invalid download error. This was broken in the work done towards build 18916 though the update check on loading does still work which is how most will likely see this & mostly affects beta testers.
Some modern skins may not draw correctly with either partial or completely missing window frames. This seems to be due to a change made on Feb 20th in the interim / beta builds to resolve seeker bar elements along with some other elements not showing as expected in the skins. A solution to keep the prior fix & un-break the skins now being reported as broken is being looked into.
The streaming source plug-in will fail & trigger a crash when the obtained year metadata is longer than expected.
Some setups when using the Milkdrop visualisation plug-in might experience random crashes due to what seems to a driver side memory leak possibly limited to Intel based igpu setups.
Making changes to the order of the library playlists may not be saved if switching the playlist / library view (there is a manual save button but may not be visible depending on the view size) as well as the currently playlist item (if applicable) not seeing it's position updated when changing the order of the library playlist items.