Project config sync not applying single's changed template path

Description

A change to a single section's template path setting isn't applied by project config sync. The specific change I noticed this with was adding an underscore prefix to the path.

Steps to reproduce

1. In one environment, change a single's template setting from "my-section/_entry" to "_my-section/entry" (or probably any other change, the prefix change is what I was doing when I hit this bug.
2. Push the change up to a remote environment
3. See that the project config file on the remote environment has the updated template path
4. Run project config sync on the remote environment
5. See that the section's template has not changed on the remote environment

Additional info

I'm not on the latest version. Not seeing anything about this in later versions' changelog notes. There's a lot going on with this particular site I'm holding off on upgrading for the moment, but can if you expect that'll address the problem.

I have not run sync with --force yet in case there's anything I can do first to help diagnose the problem.

Possibly this is #6160?

• Craft version: 3.4.20
• PHP version: 7.2.24
• Database driver & version: MySQL 5.7.29
• Plugins & versions:

Start by reproducing the project config sync flow with a single whose template path changes from "my-section/_entry" to "_my-section/entry". Compare the project config and the single after synchronization; done when the changed template path is applied on the remote environment.