I think I'm having the same issue, or a slight variation. I'm using the hover state on 99% transparent rectangles to show popup text boxes. The text boxes are set with white fill that should cover anything below it. But in preview/publish some of them have lines showing through them that appear to be from other rectangles below them. This happens for some but not all of the rollover rectangles so I'm not certain if its this bug or if I'm missing something.
See the behaviour here: https://360.articulate.com/review/content/0a29792f-ea1e-4eb8-9728-680648671cba/review
Storyfile is attached also.
Thanks for any ideas. I guess I'll submit this to tech support also as it might be the same issue.
Lon