Edit a page with wikitext [[User:Trevor_Parscal|Trevor Parscal]] ([[User talk:Trevor_Parscal|talk]]). Inspect the second link ("talk"), wait for the suggestions to load, then click out of the inspector. The save button activates. Click the save button and review the diff, and you'll see that the underscore in the link target went away.
Looking at the DM transaction history, the link was replaced with a newly generated annotation that doesn't have htmlAttributes and doesn't have origTitle or any of the orig* attributes.
For whatever reason, this bug doesn't happen for the first link. Maybe it's because only the second link has a namespace prefix that contains a space?