I noticed this morning that ATS and BRR were updated recently, and the ADU client (v18.104.22.168) installed the new versions (v1.0.25) automatically.
However, when I launched the game, I immediately noticed problems with other mods installed in ..\res_mods\0.9.8.1\scripts\client\mods.
I use a mod, WTP_SkipIntro.pyc, from WotTweakerPlus that removes the flaming logo on game launch. After the new versions of ATS/BRR were in, the flaming logo showed up. Seeing it on game load is an immediate indication that Something Went Wrong™. When I got into a match, other mods in ..\scripts\client\mods were nonfunctional as well.
When I deactivate ATS/BRR from the ADU client and relaunch the game, everything is as it should be. Since I regularly make backups of the scripts directory, I popped in the older version of ATS/BRR and loaded the game; it worked perfectly (though ADU did not like it).
I have run into this exact problem in the past: after 0.9.8 released, when I installed a script that worked well with 0.9.7 but was apparently incompatible with 9.8 and caused all other scripts to fail. Removing that script restored everything to working order as well. This is why I make backups of the scripts folder, last time just a few days ago on 21 June.
I noticed that the new ATS.pyc was the same size as the old version, so I enabled that and left BRR off, and the game worked fine. Alternatively, with ATS turned off and BRR turned on, the other mods were broken. So the issue is definitely with BRR.
Is it possible to force ADU to use the older version of BRR until this issue can be examined?
Edit: After examining the python.log, the game apparently loads all .pyc files in ../scripts/client/mods in alphabetical order; once it gets to BRR no other mods are loaded. With BRR removed the game finishes initializing all mods.