I keep getting alerts that I've unlocked achievements when I'm nowhere close to having met the criteria for it, and some of the ones that I DO have the criteria for are telling me that I've unlocked them every time I do something related to it (for example, the Restocker achievement pops up every time I buy something from main shops now).

Not really, I still unlock achievements for stuff I haven't done. I tried my first Mallarchy Pond the other day and unlocked an achievement for doing it 250 times. I looked at the ticket submitting place and it said it wasn't a place to submit bugs, so I wasn't sure what to do. I figured I would just wait it out.

the notices show the max achievement amount every time you cross a new level within the achievement. The amounts should be correct on the actual achievement page. Mine does the same thing, really freaked me out at first.

That makes a lot of sense, actually! Thanks!!