It was definitely something on my end. I tried one last thing on the steam version, which was resetting retroarches configuration files to default. Viola, the lastest shaders worked. Some games still initialized with a blank screen, but after reloading, everything ran without a hitch for the rest of the time. Multiple scene and level changes with no problems.
What I can’t figure out is what setting caused this single shader option to crap the bed. I toggled vsync settings, run ahead, etc. One thing I noted is there might have been a descrepancy with my refresh rate. For some reason I remember retroarch reporting 59hz a few weeks back but now its at 60hz, but my memory is fuzzy. Maybe its something to do with steam and windows. I’m still new to retroarch so I can’t be certain to all the ins and outs.
I decided to stick to the standalone so there’s less fuss. Either way, thanks for your patience and help. The effort you put into these shaders really means a lot to this old and jaded gamer. A lot of us have been going through rough times, so being able to recreate and revisit these long lost feelings from a more innocent age has been very therapeutic and grounding.