Weird glitch with my collection [Risolto]

For some reason, my collection contains a Japanese 5 yen coin that I can't seem to remove. Any idea what's up with this?

EDIT:

More accurately, it contains the absence of the coin. It's listed as having a quantity of 0, but it's still there for some reason.

Probably, there is some text (or space) in the personal comments field. That, too, makes the coin appear in your list.

Cita: "ArnoV"​Probably, there is some text (or space) in the personal comments field. That, too, makes the coin appear in your list.

​There isn't.

Cita: "binarystep"​

Cita: "ArnoV"​Probably, there is some text (or space) in the personal comments field. That, too, makes the coin appear in your list.

​​There isn't.

​Oh yes, there is

Yeah that's a remnant of the migration after I separated the two styles, if you can delete this [昭和二十七年 Y#72 - transfer & delete] it should go away. I thought only I had this comment remaining .

Alright, deleted that, but it's still there.

Hm, the deletion solved it for me.
What if you try put a number in a grade box, press F5 then delete it again and press F5 once more?

Alright, never mind, looks like it disappeared on its own.