NOT fully overwrite files when copy

Describe the bug

Recently I found AFM not work as expected when copy some plain text files, the contents in the copied file seem not fully overwritten. In my case, I copy the src file foo.txt to annother folder, which contains a the dest file named foo.txt as well. Both two txt files have diffrent text contents. When I excute the copy-paste action and then click overwrite button in the paste confirm dialog, the job finish without any exception. But when I open the copied txt file(the new dest txt file that should be overwritten), I find the contents of both the src txt file and the dest txt file which before the overwrite.

To Reproduce

Steps to reproduce the behavior:

1. Create a foo.txt in path /some-test-path-1 with content 'aaa';
2. Create another foo.txt in path /some-test-path-2 with content 'bbbbbb';
3. Copy the /some-test-path-1/foo.txt and then paste in folder /some-test-path-2, click 'overwrite' button in the next confirm dialog;
4. Open the /some-test-path-2/foo.txt after the copy-paste job finish, then you will see weird content 'aaabbb' instead of 'aaa'

Expected behavior

The original file should be fully overwritten by the src file content. In the reproduce case above, that should be 'aaa'.

Screenshots

None

Smartphone (please complete the following information):

• Device: Google Pixel 5
• OS: Android 11
• Rooted: No
• Version: 3.6.5

Additional context

None

Start by reproducing the copy-and-overwrite flow on Android 11 with the described foo.txt contents, then trace the file-copy path used by the paste confirmation. Done means overwriting a longer destination file leaves exactly the source contents, with no trailing destination bytes.