Hello Mike,
I am not sure, how should I test just with VcXsrv, I tested with different versions of x2goclient where are also tried to replace directory x2goclient/VcXsrc with different versions of VcXsrv.
The last attempt was
x2goclient (4.0.5.0) / VcXsrv (1.14.3.2) - everythin OK
x2goclient (4.0.5.0) / VcXsrv (1.15.2.8) - everythin OK
x2goclient (4.0.5.0) / VcXsrv (1.17.0.0) - bad accented characters in clipboard
It looks like clipboard syncing would work only for iso8859-1 characters.
Best regards Pavel