I'm observing a difference in the .ini handling that probably accounts for this issue.
If I create a mame.ini with mameui64.exe it's missing its full inipath line. It just has the home directory. This is different from the baseline .exe which creates a .;ini;ini/presets that lets you get to the raster.ini.
If you run 'mameui64 pongf -hlsl_enable' with the mameui produced mame.ini it doesn't find the raster.ini and doesn't show the mask/aperture effect (although it's probably running hlsl with the default non-impressive settings from the mame.ini section)
If you put the mame.ini created by baseline mame64.exe into the home directory of mameui and run the same command line it works as it finds raster.ini.
So the support files would seem to be ok in my dist package; it just appears to be the .ini handling in my estimation.