Checklists: Check List Boxes Replaced With OBJ (object replacement character)

#### Steps to reproduce
1. Add a checklist to a note in MacOS App and all the lines of text in the note are moved over slightly instead of adding checkboxes. No checkboxes are showing (screenshot 1)
2. Open the same note in Android and checkboxes show (screenshot 2)
3. After a while, the same note on Android has its checkboxes replaced with the OBJ symbol.

*Additional notes*:
When I selected and copied the "space" (not an actual space, but an empty area where a checkbox should be), I had it in the clipboard.

When I paste it in the note elsewhere, it doesn't show on the Mac, but does show on the Android app, not as a checkbox but as an OBJ symbol.

When I paste it in a Mac web browser, it shows as the OBJ symbol and looks like the one on Android.

#### What I expected
See checkboxes normally

#### What happened instead
Checkboxes do not show up in MacOS App, but only in Android App but then disappear even there.

#### Simplenote version
Latest (both Lite and Dark theme)

#### macOS version
Latest

#### Screenshot / Video
1.
2.
3.

Reported in 1963884-zen

No source files, tests, or entry points are named in the report. Reproduce the checklist behavior in the macOS and Android apps, then trace how checklist text is rendered and synchronized; done means checkboxes remain visible and consistent across both clients instead of becoming OBJ characters.

Written by the indexing model from the issue text.