Thermoquad leak

I disassembled the tq I’ve been running for years, and I found the pockets in the base that the jet wells sit in were full of fuel. It’s Vp c-12 and was kind of jelled up. This is a drag car that has been sitting since October. I know it’s a common problem for them to leak. So I filled the bowls with mineral spririts, but I can’t detect a leak.
Could the fuel be from somewhere else?
Could the bowl only leak when under stress when the carb is assembled?
The floats and needle and seats are in good shape, it’s not flooding over.