When opening certain items with "Open with", a flatpak address is aready there. However, the app itself doesn't appear. The issue is either one of these: 1- Flatpak addresses doesn't work for finding the app with their proper name. 2- "Open with" should search the proper name of flatpaks, instead of address.
Confirmed on master. Also, please use the bug report template next time.
Is this the same as bug 508469?
Yep, looks like the same thing. Yours is newer (and not in the right place), so I'll make this the master bug report for it.
*** Bug 508469 has been marked as a duplicate of this bug. ***