It was also reported as a bug:
With todays [sic] patch, the timer on stun has been reduced so you can't get a recast to land before the stun breaks. This lets the targeted mob run up on you or merc before a new stun can land. This change was not in the patch notes. This is using dizzying gyre.The only response noted from SOE has been:
We're having a hard time reproducing this. Is there a particular zone / mob that is occurring on?Which seems to indicate that it is a bug.
In the seven days since this was reported by multiple people, no further comments or information from SOE has been heard. Hopefully, we will soon get at least an acknowledgment that it is a bug and being worked on.