With those settings a client should not be dropping from the wireless. You should contact the GTAC so someone can review your configuration settings. Have your tech support generated and ready before you reach out.
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-Collect-a-Tech-Support-File-From-a-...
Also please document the following:
-How many wireless clients are seeing this issue
-Are they all the same type of client device or multiple device types
-If it's only the same device types, document the card type and driver/software versions you are using
Doug Hyde
Director, Technical Support / Extreme Networks