The pedal is wearing/binding on the plastic shaft on which it rides. This can be
checked by lifting the front of the pedal with your toe.
If it stops seeping, you found your problem. It. Will be an intermittent problem until
either the pedal flies off or the bowl overflows.
The inexpensive fix is to buy your Dometic 310 and replace promptly, or keep chatting
with Thetford techs who claim to be unaware of any problems and recommend you buy
their rebuild kit for $40.
This is a common problem if you use the search or Google the problem.
Hopefully you'll get this solved before the toilet overflows.
Leprechaun 260 DSF
2017 Big Horn FL3750
'10 Yellow Lab to keep us on our toes.