We experienced a issue in our environment that all the desktop published on the citrix servers
were showing the sign of hung.
We have tried number of things but we were not able to rectify it.
In the end we checked by chance that Terminal License server ip address in DNS is pointing to the ip that doesn’t exist.
Fixing the ip address in DNS resolved the issue.
Still I am not convinced why the servers got hung as it should wait for grace period or throw some error but we were able to reproduce it as many times in our environment , so theoretical things are not always good in practical situations.