Inconsistent lock icon display when enabling/disabling permissions

Distribution

Mint 22.3

Package version

nemo 6.6.3

Frequency

Always

Bug description

A file (current.png) is marked as read-only (all Write permissions unchecked) but does not display the lock icon. Checking the file actually shows as no write permissions enabled. If I copy and paste the file, the new copy also does not show the lock icon and it also shows no write permissions.

In contrast, another file (scenario.png) correctly displays the lock icon. But, oddly, when I copy and paste it the new copy does show the lock icon but it not carry the permissions; i.e., the new file has write-user and write-group enabled.

I'm not sure what is the correct behavior regarding the copy of the file (keep permissions or not) but it is not consistent and the missing lock icon is just strange.

The two .png were created from a screen shot so are just normal images. The two .xlsx were downloaded from a site and are just regular sheets.

Steps to reproduce

I copied four files into a folder. I then selected all four, right-clicked and unchecked write-group and write-user; then clicked close.

I noted that "current.png" did not display the expected lock icon while the other three did.

Investigating, I found the lock icon appears or not in conjunction with the write-owner setting.

Despite having no lock icon, "current.png" does show write-user and write-group as disabled.

The same as "scenario.png" which does display the lock.

When I copy "scenario.png" and paste it (creating "scenario (copy).png") it shows that the permissions have been reset to default; i.e., write-user and write-group are enabled.

When I do the same with "current.png" (creating "current (copy).png") it also does not show the lock but it does retain the permissions were retained; i.e., write-user and write-group are retained.

Expected behavior

I would expect the lock to appear consistently in conjunction with the write-user setting. I'm not sure why this file, filename, position, something is different.

Additional information

No response

Start by reproducing the behavior in Nemo 6.6.3 on Mint 22.3 using the four files described, then compare the lock icon with the write-owner permission before and after copying each file. Investigate the code paths responsible for permission display and file copying. Done means the lock icon is consistent with the write permission and copy behavior is consistent for these files.