Auto Upload does not delete files and generates error message if subfolder year/month is set

### ⚠️ Before posting ⚠️

- [x] This is a **bug**, not a question or an enhancement.
- [x] I've [searched for similar issues](https://github.com/nextcloud/android/issues) and didn't find a duplicate.
- [x] I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/).

### Steps to reproduce

The error relates to the auto-upload if it is set to delete the original file and also to organize it in subdirectories with year/month.
I have translated the information on the menu items and error messages from German into English; they apply accordingly and may not be congruent with the English version of the device.

1. Open Settings, Auto Upload
2. Select an auto-upload, activate it and specify the remote folder
3. Activate "Include existing files"
4. Activate "Use subfolders"
5. Set subfolder options to "Year/Month"
6. Select "Deleted" for the original file
7. Under "What to do if the file already exists?", set the version on the server to be overwritten.
8. Save this

Any files that arrive are uploaded. However, some are not deleted as configured. Files that aren't deleted generate a "Folder error" or occasionally "File missing" error message in the notifications. This can also be viewed under "Uploads."

### Expected behaviour

The files are uploaded with these settings, deleted from the original directory, and the error message is not displayed.

### Actual behaviour

Any files that arrive are uploaded. However, some are not deleted as configured. Files that aren't deleted generate a "Folder error" or occasionally "File missing" error message in the notifications. This can also be viewed under "Uploads."

### Android version

15 Graphene OS

### Device brand and model

Google Pixel 7 pro

### Stock or custom OS?

Custom (explain in "additional information")

### Nextcloud android app version

3.31.0 but also earlier

### Nextcloud server version

31.0.2

### Using a reverse proxy?

I don't know

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_