just in case, could it be that some of the files you copy from gemdos HD
have "strange" attributes/ownership ? Or maybe a date that appears to be
in the future ? or similar things ?
Surely not, because the problem goes both ways -- I copy some stuff to floppy (usually on TT, due to this problem) and then I want to launch it from floppy on Falcon and boom. So whatever could have been wrong with HD, there's no chance it's still there on floppy.
If you find time, try to copy something to that disk image I attached earlier. Will be interesting to know whether writing works for you with my cfg.