Despite an old post, a relevant aspect (maybe) can be gleaned.
Stirring properly and following can instructions may have been a part of th
e OP's problem, but I think moisture contributed to the issue.
The OP said the wood was stored in the garage (in essence, outdoors, cold t
emps?), yet the work place was a "heated porch". He/she said the wood "...
"feels" moist". He/she may not have allowed the wood's temp to acclimate t
o the work place's higher temp, hence, there may (likely?) had been slight
condensation on the wood surface. I assume, quick condensation formed on t
he can's lid, also, apparently (again, I assume, by what the OP said) immed
iately after opening.
In the OP's (I assume) colder climate location, plus the garage vs heated p
orch immediate environment, there may have been a significant temp differen
ce to cause some condensation, despite his/hers generally dry climate. A s
ignificant temp difference, from garage to work place, can negate the gener
al dry climate arena.
Op said he/she had used the product, before, with no problems. What might
have been the difference in the two work scenarios, circumstances.... Weath
er conditions, prep conditions, temp acclimation, something else, including
Where was the poly stored? Was its temperature greatly different from the
wood and/or porch area, also? ...and compare this to the previous "no prob