Bug? with editing attachment points

I created a note by reference against Mark 6:1-6 in the NIV

I then realised that I actually wanted to link it to just verses 4&5.

So I edited the attachment points, adding a reference to Mark 6:4-5 and deleted the one for Mark 6:1-6

However the note icon still appears at the beginning of Mark 6 in the NIV as well as verse 4.

When I open the ESV the note icon just appears (correctly) for verse 4-5