I created a work, which turned out to be duplicate, so I merged it, but after the merge there is a duplicate link to IMLPS.

From my understanding the merge process couldn't check if the links are duplicated, because it doesn't compare links with regular commas with the one with escaped ones:

1) MajorLurker added a link. It contains the escaped comma (it uses "%2C")

2) I added the same link without escaping.

3) After merge both are present on the page of Work.

I think, either editor should filter out the escape mnemonics (or add them), or the merge process shouldn't add escaped/unescaped link to already existed one.