Telegram keeps notification settings after deletion
I had installed Telegram last month & then deleted my account after a while. After a few days I created the account again & joined the same groups I had joined before deletion. Surprisingly they were muted, I joined a random group just to check if it's the default, looks like it isn't default.
I deleted the account & was able to reproduce this again. Today, I created Telegram account again thinking they might have cleared everything by now but noticed the same behaviour again. For now, I've set my account to delete after 1 month of being idle & just uninstalled the application. I'm hoping that the data will get removed in automatic deletion.
I reported this issue through their support form.
2020-09-06
I changed "channels" to "groups" on this page, got confused between the two.
I checked again by joining a third group that I've never joined before & as expected notifications were enabled by default. Then I joined another group which I had joined before (and muted), the notifications were muted. This was between re-installs so it's not locally stored data on my phone.