Having issues with users reconnecting a disconnected Citrix Virtual Apps and Desktops session? These keys might help you. Citrix support confirmed, that they help starting at Server 2016 VDA.
Fastreconnect is a feature that was introduced by Microsoft to enhance session reconnect through RDP, but through Citrix ICA it seems that is does not improve anything.
FastReconnect REG_DWORD 0
EnforceUserPolicyEvaluationSuccess REG_DWORD 0