You shouldn’t.
That was all good & relevant information.
I couldn’t understand how a vac leak during SPD would send distillate to the cold trap. But I think I’ve got my head wrapped around it now.
However, I was just (4days ago?!?) regulating the vac on a rotovap (first time it had been used) at the feed valve, and it was pointed out to me that we were getting reflux but no condensing. Turns out the cold air in rush was condensing everything and dropping it back into the boiling flask.
@tweedledew then grabbed his version of a controlled leak (poor mans vac controller), closed the leak at the feed valve, and off to the races!!
I’m betting the OPs machine would leak until it (suddenly) didn’t, at which point it sealed and bumped.
Any reduction in vac, and it would leak again. Either dropping his solvent back into the boiling flash, or whipping it by the condenser so fast that it hit his pump.
@PrimO.Oil it’s possible @Xtractek might have one of those on hand (it’s usually the glass that breaks 
).
looking at the failure mode suggests it might have been over tightened…although contacting the manufacturer seems like a decent response too.