Misleading license detection for Declared License in scan results of AppFlowy-0.9.8.tar.gz

A recent scan of https://github.com/AppFlowy-IO/AppFlowy/archive/refs/tags/0.9.8.tar.gz returned some strange and unexpected results in the "declared" fields:
```
declared_license_expression "unknown-license-reference"
declared_holder "Free Software Foundation"
```
the scan was done with
`tool_name: "scanpipe", tool_version: "35.3.0", notice: 'Generated with ScanCode.io ...`

Oddly enough, the license clarity score was 100, even with the unknown-license-reference. I cannot figure out how that happened from the scan results.

Note that the README.md has the following at https://github.com/AppFlowy-IO/AppFlowy#license
`Distributed under the AGPLv3 License. See [LICENSE.md](https://github.com/AppFlowy-IO/AppFlowy/blob/main/LICENSE) for more information.`

Scan results attached.

[AppFlowy-0.9.8.tar.gz_scan.zip](https://github.com/user-attachments/files/22222865/AppFlowy-0.9.8.tar.gz_scan.zip)