Yes it'll cast group C with nec on target like the picture. Nothing is blocked. Must have really screwed something up because now he won't cast lich anymore.
Well the necro definitely casts lich if it can use lich on the necro.
I'm leaning towards this is something wrong with the way you have things setup somehow.
All I can do is take the information you're providing and test to see if it's valid by checking those things in game.
Since up to this point everything you're saying we've checked and it's working as intended on our end.
I would also point out that if this were not an issue with something on your end then other users would be reporting the same.
So something you're doing or the way you've got MQ installed etc is likely the problem. It's just a matter of determining the issue.
So lets go through a list of things.
Is the necro in your group?
If not, are they on XTarget with XTargetBuffing on?
Is your MQ stored in a network drive like OneDrive-DropBox-or something else that could cause those files to be locked.
Have you excluded the MQ folder from virus scanners.
Have you loaded either a class plugin, or MQ2CWTNBuffs?
If you cast these spells manually, do you get any output from EQ about it, such as not stacking blocked by something else, doesn't land on them for one reason or another?