There is some error in material replacement code.

Lets have 2 skills, both with different status effect and both of those status effects have material replacement:
#1: duration 10 sec, replacement A
#2: duration 20 sec, replacement B

If you use skill #1, material is replaced to A. Now use skill #2 before skill #1 ends. Material is replaced to B. Skill #1 ends before skill #2. Material B is correctly preserved. But problem is when skill #2 ends, material is NOT restored to the original material (ie. before skill #1).

This can be observed during the combat randomly, where lot of material replacements can occur.

Example is Priest with Skaal subclass. During the combat, cast Shadowing Beyond. Right after you get invisibility (material replacement #1), cast Minor Avatar. Minor avatar has long cast time, but you should be able to get it cast before shadowing beyond ends. Now Minor Avatar does material replacement #2. Invisibility from Shadowing Beyond will end during Minor Avatar, leaving material replacement #2. But when Minor Avatar ends, you are stuck with material replacement from that skill.

Forget about it. Whole game is indian code.

Sadly, I bought the game just few days before 5.0 release when the support ceased ...