Part response to your PM as well...
I'm at a loss what to do with these poly tops. If I don't tighten them in enough, people yank and twist on them trying to pull off old tubing and then complain to me that they've gone and half-twisted out the barbs. If I tighten them up enough so that this doesn't happen they get dangerously close to the point of cracking where even a little bit more tightening will cause what you saw.
The correct solution to the small leak would have been to take the barbs out and reapply silicone sealant and put them back, but not too tightly. Unsure how the small leak developed for you in the first place. I've run anything from -5C to 50C liquid through multiples (at least 5) of these tops in my own testing and never noticed issues. Perhaps just a random bad seal? :shrug:
In any event, will send another top your way. Just PM me your address again.
Your board will be fine so long as you give it enough time to dry. As an additional drying method I highly recommend a vacuum cleaner with the "beak" nozzle fitting. Great for sucking out droplets from delicate places in between IC pins and things. Have had boards that would not come back to life until taken to with the vacuum cleaner.