"?" In character names with custom playerslot.txt files "disappearing" characters.

[Flints]

Bug Report -
Unique Condition 1 - Requires you to use "custom playerslot.txt" file.
Unique Condition 2 - Requires that custom file to be set to "read only" (Because that's the point of it).
Possible? unique Condition 3 - No other characters in your player sheet with the special character.

Bug itself -

If you rename a toon, to include a "?" That toon disappears from the character selection screen.
 
Additional.

Restarting will not solve this.
Search function will not contain the "missing" character.
- With the weird exception that, once it's

Other special characters that don't trigger this -

-
'
.

Attempts at Recreation 3/4

Possible reason for 4th recreation failing.
Once the "<Name>?" Character had been found in search, they I suppose were "in the system" so removing the ? with a rename and naming again with ? didn't cause any bug.

Suggestion for GM notes to players -
If a player reports their character "suddenly disappeared" after a renaming, ask if the name included "?" and they've got a read-only playerslot.txt file.
Suggest that player turn off the read-only, by making a backup, to see if character has "returned"
Let player know they'll need to manually update their read-only playerslot.txt file, with the name of the renamed character including the ?" character.