Users randomly get disconnected when using XenApp 7.16.
This has been fixed in XenApp / XenDesktop 7.17 (LC8937). A Hotfix is also available: CTX231127 - LIMITED RELEASE - Hotfix ServerVDACoreWX64_7_16_001 - For VDA Core Services 7.16 for Windows Server OS (64-bit) – English.
Known issue with 7.16 - LC8937 - “Session Disconnect On Computer Policy Refresh” issue. Computer policy refresh causing subsequent random user disconnects due to ICA-Listener refresh.