oof that might be the culprit.. These syringes are Polypropylene, with Isoprene rubber plunger tips. (That seems to be the standard with single use non-medical plastic syringes.) Isoprene / natural rubber has the worst rating for chemical compatibility to ethyl acetate on all of the compatibility charts I just looked up.

I'll do a test as you suggested.

I've also wondered how the seals fare on mason jars and if that's a storage problem in general. I always try not to let any EA come into contact with the lid seals. But even the 'silicone' red seals on some jars I've used with ethyl acetate seem to have dried up rapidly. 2 other jars I had used EA stored in had their seals start peeling from the steel lids...

EDIT: Maybe my lids were just old though