Currently, original teachers don't get access to their lessons if there are substitutions assigned to this lesson. This has to be fixed and we should check if there any similar issues.
When drafting the access model in Alsijil, compeltely transferring the complete teacher role to a substitution teacher was intentional because only one teacher should be able to author notes for a lesson at any given time.
If this is to be changed, it needs to be discussed.
Then again, we already depart from that, because nowadays lessons can have more than one teacher. Thus, we should probably treat substitutions the same as co-teaching…
First, you should provide argumentation. If you support my first position, or maybe the option to make the lesson read-only for the regular teacher, please document why. (Same for all other options; we should not make changes because someone says it might be a good idea without reasoning).