You don’t have the PCD do you.
You’ll have a tough time finding the fault or errant signal without it.
Seems odd. The Ascension 1000 for it’s time was sort of smart. If limits are both open, it would be faulted and not open the doors at all. So how it answers at the top from the bottom hall call is weird.
Parking and other options are done on the Personality Board via jumpers, but without a manual for the 1000 you’re out of luck. About the only thing I can say is check the 5volt supply, and tape magnets.
Does this unit have Fire Recall type feature? Maybe a short in the button box wiring somehow (just my WAG).