Strange Reveal Modal Behavior

I have a site that is creating a view with 200 rows of image file names. Each file name has is a link to a reveal modal that displays an image of the file.

Only the first dozen or so rows are shown in the initial viewport. If you click on a file in that initial viewport display, the modal is displayed over the page contents with the viewport contents visiable in the background.

If I scroll down some and click on a file name below that initial viewport list, the modal is displayed as expected, but the background is blanked out after the last row of the original viewport display.

The following screen shot shows the problem.

The code is behind a user log in so it's not easy to provide a working example at the moment. So what I'm after as a first step is to determine if this is a known issue. If it's not a known issue I will move to step two and work on creating a working example that highlights the issue.

Your description is not very clear.

edited Jan '19

Yeah, it's a bit hard to explain. I'll probably have to find a way to write a small test case unless I luck up on someone who has dealt with the same issue and understands what I'm trying to describe.

I can add a "before" and after screen shot that shows what the screen looks like before the reveal modal is displayed.

before...

and after...

So everything after the second file name is hidden. After the modal is closed, the content of the view returns to the "before" state... meaning the data is all there. The reveal modal display is redering the data hidden in some way that I haven't been able to identify yet.

The background is also changing to the gray that is shown.

It's a really strange problem for sure.