BUG: Reading Plan Completion Link Missing

I've been using reading plans for ages, and generally I love them, but there is one little bug that appears on iOS - it doesn't appear on the Mac or on Android. 

I have a plan set to read through segments of the Greek New Testament, and when a reading finishes on a chapter division, the "Mark Read" bar isn't present. It is on Android, but not on iOS. If the reading finishes part way through a chapter it is present, so this is only when a reading finishes on a chapter division.

FWIW, I'm using the UBS4. I think I've struck the same thing with the NASB, but I don't have a NASB reading plan at the moment, so it may not be an issue.

This bug has persisted for ages, and I thought it would eventually go away. I guess not

Thanks!