It's essentially latency related. It's always occasionally been a problem, but mind you that it's not necessarily a problem of *your* connection. The reason so many people are seeing it suddenly is because the duty servers are more loaded than they have been in many months, with a lot of players new and old playing that weren't before. Mudras face similar problems in duty servers (compare using them in the residential district to using them in the raid/Coil server on a Tuesday night, for instance).