And for me, it isn't happening at all. Like the other David, I mainly highlight to fix errors, but I recent short story I was reading probably averaged an error per paragraph. Marking these (well most, of them as I tend not to mark repeated errors) worked with no issues. This was on my Aura H2O. A quick test on my Glo HD and I have 10 highlights and annotations on the first page of the book with no problems.
Maybe it is something strange with the Aura HD.
Long presses barely work in 3.15 discusses other annotation problems with 3.15.0. From memory of that thread, it seemed to be a lot more common with the Aura HD than any other device.
Two things missing from your report:
- Book format - epub or kepub or both.
- Does it happen for annotations or highlights? The selection is the same, but adding the note might change the behaviour.
- Is this single word or selecting multiple words?
I probably should add that I am not using 3.15.0 or 3.16.0 on either device. I have a "later" firmware version. But, I haven't noticed any real changes in the annotation behaviour recently. There was a bug added in 3.15.0 that affected the last word of a paragraph going over a page, but nothing else.