Welcome back Mike,
Yeah, it looks like a theme issue. I checked the code of 2 pages to compare.
This is your events page:

You can see that you have a row, and in the row the 2 columns are nicely there.
This is your event submit page, where the sidebar column somehow falls outside of the row.

(Sorry for the rough sketches.)
So you can try to check around in how those pages are set up, if it’s possible.
This css snippet does help a bit, but it’s still not perfect:
.tribe_community_edit .td-main-sidebar { float: right; }
Does this help get you started? Let me know.
Cheers,
Andras