If you are a ES sorc or a paladin, avoid skill shrine like a plague. Let me explain.
Both energy shield and holy shield have a same feature(or bug?): lower lvl re-cast does not overwrite earlier higher lvl cast. Therefore, if you casted energy shield or holy shield with skill shrine, your re-cast of ES or HS later without shrine will simply be ignored, and the old ES/HS will finally expire, typically at the worst possible moment. Note you don't always notice the missing ES/HS inmmediately.
This was not too bad before rotw, because reasonable level HS and ES last much longer than a typical TZ run, except maybe tal rasha tomb tz. Nowadays with rotw and whole act tz, game lasts much longer, and this becomes a problem.
similarly, when you don't have CTA and someone battle command you, same problem: once you cast ES/HS with battle command, your later recast will be ingored.
When in doubt, simply exit and re-enter the game and cast ES/HS at your typical skill level. same level re-cast will refresh the duration.
enchant is similar too, but when the cast fail to overwrite, you can notice it, and it is not an essential survival skill anyway.
btw bo/shout always overwrite.
Didnt know that. Precious intel here. Now I understand why sometimes I end up without HS while I recently recasted it.
Thx
Funny thing tho is lower lvl BO overwrites the higher lvl so this thing isnt as obvious as it may seem