You 'may' be having issues with songs landing...
If you have an enchanter and/or shaman in your group..or have combat procs that may interfere with certain songs..have you tried
looking into these types of conflicts?
The previous problem with certain songs was that their recast delay/buff duration were both 0 and that song was always available
as a priority 1 during the next spell casting cycle.
That should be addressed though, by this:
https://github.com/EQEmu/Server/blob...llsai.cpp#L923