Annotations that are supposed to appear after the 01:00:00 mark on a YT clip end up appearing exactly one hour too soon. In other words, if an annotation is supposed to appear at 01:01:34, it appears in the downloaded clip at 00:01:34. The .srt file created for the clip is incorrect.
An example: https://www.youtube.com/watch?v=bOBibhv7Q_8
Otherwise, 4KVD is a great program.