Previous update files were removed on OS update

Summary

Previous update files has removed on OS update although preferences has been set to keep update files.

Steps to reproduce

Update from 0.19-q to 0.20-q.

What is the current behavior?

Old updates are not showing up anymore under System updates.

What is the expected correct behavior?

Old update files shall not be deleted, if preferences say do not so.

Relevant logs (adb logcat)

Relevant screenshots

Workaround

Possible fixes