[Bug]: Client changes file content while writing (version 3.15, 3.14, 3.13; 3.12.3 okay)

### ⚠️ Before submitting, please verify the following: ⚠️

- [x] This is a **bug**, not a question or a configuration issue.
- [x] This issue is **not** already reported on Github (I've searched it).
- [x] Nextcloud Server and Desktop Client are **up to date**. See [Server Maintenance and Release Schedule](https://github.com/nextcloud/server/wiki/Maintenance-and-Release-Schedule) and [Desktop Releases](https://nextcloud.com/install/#install-clients) for supported versions.
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/)

### Bug description

Manipulating the content of a .md file through Logseq in a synced folder has unexpected behaviour with client version 3.13 to 3.15, version 3.12.3 seems to work correctly.
When I write few lines in the text file and then try to change some lines above the content changes unexpectedly and the client shows file conflicts.
There is only one user of the shared folder and I only manipulate it locally.

### Steps to reproduce

1. Write content into a file inside a synched folder
2. Manipulate some lines which are not at the end of the text file
3. See content removed from the file
4. Nextcloud client shows file conflict message

### Expected behavior

The client should not manipulate the content of the file that is only changed locally.
No file conflict should happen.
...

### Which files are affected by this bug

example.md

### Operating system

Linux

### Which version of the operating system you are running.

elementary OS 7.1, Ubuntu 22.04.5 LTS, Linux 6.8.0-48-generic

### Package

Official Linux AppImage

### Nextcloud Server version

28.0.12.2

### Nextcloud Desktop Client version

3.15 down to 3.13

### Is this bug present after an update or on a fresh install?

Fresh desktop client install

### Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

### Are you using an external user-backend?

- [x] Default internal user-backend
- [ ] LDAP/ Active Directory
- [ ] SSO - SAML
- [ ] Other

### Nextcloud Server logs

```shell

```

### Additional info

_No response_

Start by reproducing the behavior with Logseq editing example.md in a synced folder on Linux, comparing client versions 3.12.3 and 3.13–3.15. Confirm that editing lines above existing content does not remove content or produce a file conflict; the issue does not name an implementation file or test to inspect.

Written by the indexing model from the issue text.