I tried copying & pasting from that html and still didn't see any oddball boxes. BUT! since the metadata for that html indicates it was produced with Word 97, I'm betting it was a weird Word character that the default font in AS didn't want to render or was the result of some character encoding mismatch.

Thanks for checking into this! Actually, I checked my finding aid and I think the boxes are gone now and I forget whether it was by the pain of student workers or possibly through incremental ArchivesSpace updates. Here is a sample HTML inventory we were using to cut and paste from:

Thanks for working on this!

I created a resource and AO with trailing whitespace and the new background job successfully removed the whitespace.

However, I'm not sure how to reproduce the original issue so I'm not sure I'm fully testing the solution. I did not see the boxes as shown in the png attached to the issue even when whitespaces were present.

It almost looks like the original issue was a copy/paste of some odd character that is not rendered by the default font (maybe from word or via word) rather than a whitespace issue.

We have added a background job called "Trim Whitespace" which removes leading and trailing whitespace from titles for resources, accessions, digital objects, archival objects, and digital object components.

Seems like it wouldn't be too hard to find trailing endspaces at the end of unittitles in the staff user interface. I think the bigger question is whether this is something the larger community desires.