Mason jar didnt seal properly.

[Mike1ranger]

Today, I discovered a jar from this years batch didnt seal properly. Noticed some moisture on the outside of the jar and thought it was odd so checked the button of the Mason jar lid and it wasnt down. No mold or other visual signs of issues but not sure if 3 month old jar of syrup has gone bad. Thoughts?

[maple flats]

It is still good. Issues that could have caused it not to seal, something on the rubber part of the lid, temperature of the syrup not hot enough or something on the top surface of the jar. There could be other causes too. Just be glad you found it early. Put it in the fridge and use it next.
As long as the syrup was at proper density, maple syrup does not "go bad". It may get some mold on top, but if some ever does, heat it back up to 180-190F, skim the mold off and the rest is good.