I haven’t seen this kind of issue. One thing I observed is that with versions before 19.3 (FMS and FMP), reconnection after client wake-up failed frequently.
What are the concerned versions of FMS and FMP in the case you describe?
One option that could solve it is setting the ‘flush cache’ in Preferences to a delay shorter than the delay for the computer entering sleep mode.
Is disconnecting clients after an idle period activated on server?