I'm having the same "issue" with the mudras getting locked up randomly, like hours and hours (sometimes not at all in a ten hour instance) apart in when it happens, seemingly whenever I'm on the move or the boss is from what I've noticed. It gets locked up, starts spamming one mudra over and over again for a second or two before resuming the rotation. Lag hasn't ever been an issue for me on FFXIV, running 300 down 110 up, not entirely sure if it could be frame related or just something that's unavoidable.
edit: Had it happen a bunch more today, but only when it was AoE'ing. Only other way I could replicate it was using a mudra before it did, which would obviously mess it up anyway. But when it was Aoe'ing and something would die or move out of range, it seemed to lock up on the mudras for a few seconds having messed up.
edit2: After having it lock up a bunch in an expert dungeon, I narrowed it down to one particular ability so far. It tries to cast something, usually raiton? But for whatever reason it actually mixes up mudras and does Hyoton, which ends up with it trying to cast an ability it can't cast until the mudra buff times out.
edit: Had it happen a bunch more today, but only when it was AoE'ing. Only other way I could replicate it was using a mudra before it did, which would obviously mess it up anyway. But when it was Aoe'ing and something would die or move out of range, it seemed to lock up on the mudras for a few seconds having messed up.
edit2: After having it lock up a bunch in an expert dungeon, I narrowed it down to one particular ability so far. It tries to cast something, usually raiton? But for whatever reason it actually mixes up mudras and does Hyoton, which ends up with it trying to cast an ability it can't cast until the mudra buff times out.