Bug: get_post_gallery() on 7th execution

Hello,

I just discovered interesting bug that get_post_gallery() returns for me bool(false) on 7th execution in list views (option posts_per_page: 10).

This is sure bug in execution – the same post structure and when get on list views with something else (e.g. category, gallery post format etc.), there are no problem.

I am using twentyfourteen modified directly (I hate child themes so much), but tested also without modifications could have an impact on that. I am using get_post_gallery() for adding link to go/scroll to gallery (to own #gallery).

Example screenshot

Greetings