This is caused when using Teradici APEX 2800 Server Offload Cards with the apex software 1.1.0 “apex2800-1.1.0-rel-14288.exe”.
On Page 23 of TER1109003_Issue_2_APEX_Administrators_Guide.pdf (TER1109003-2) it states
Note: The APEX 2008 card does not currently support client image caching. This will be added in a future APEX 2800 software release (within the second half of 2012)
By default in View 5, image caching is set to 250mb. In a LAN environment the effects are not noticeable however when a user is remote the experience can be poor. The client devices can experience high cpu usage due to packet loss with can be seen visually and by using a great tool called PCoIP Configuration Utility (beta)
The fix is to either turn off offloading for any remote users or update to software release 2.0