The top hole is only 1.2mm and the slot is 0.6mm wide, so if your filament is soggy, your slicing is bad, or your printer isn't set properly, you might have to print a second time. The good news is, it'll come in around 0.25g of filament :).

I printed 0.12mm and 0.20mm layers on two different printers and had pretty good results. So undried PETG performed the worst with a little stringing, but that was an easy x-acto fix.