MC 1.12.2, Forge 14.23.0.2515, AoV 0.7.3, SSP
The caster's visual effects for searing light and other spells just do not work anymore. The searing light still kills but instead of a white line of particles there's a sparkling white cloud behind the caster which stays put in the air. All spells do work but the visual effects are messed up somehow.

Your image shows the spells as they should work. Something told me that starting over could be an effort that could help. You see, I tell my useers at work to start over if they have problems. So I restarted Minecraft from scratch and now it works for me, too. I did not change any setting and cannot reproduce the issue but have screenshots of the "clouds". The effects are back and working normally again.

Seems to be working fine?