Note that Fusion does not support PCAS for mode C transponder yet (it is supported for Mode S).
What is reported here is TIS-B.
A glider with powerflarm and Mode C transponder will he shown as 2 targets one near the other (flarm and TIS-B) at least part of the time. This is expected behavior.
For the glider with the mode C transponder they will see a ghost of their own aircraft most of the time. This should not be an issue with Mode S transponders. So owners with mode C transponders and fusion may want to consider disabling the TIS-B only (not ADS-R and not PCAS) if the ghosting bother them.
I described in another thread how to do it.
Ramy