Non-printing layer somehow gets printed

Thanks everyone.

All settings on my end were correct. I've checked my layers in Acrobat, all layers should should be invisible are turned off.

It seems the printer, like mentioned by you guys, did not respect my layer settings. Probably someone skipped their cup of morning coffee or something. Will have a chat with them. 🙂

You'll have to chat with your printer. Some RIP workflows (like Prinergy) have options to set on how to handle layers, no matter how they are set. Normally, the settings are to honour the layers attributes, but this can be overriden, annnnd If, say, they set their automated workflow to "ignore layer viibily and print everything" then there's a definite problem with that.

Who's to blame? the printer, especially if any proof you received was correct.

Did you export the PDF with Acrobat layers included (checkbox in the export dialog)?

You can check your PDF in Acrobat: if there are layers then there is a layers icon in the left toolbar:

If so:
All layers (non-printing as well) get included in the PDF but non-printing layers would be invisible.
Maybe the printer didn't respected that setting and printed all layers.