It happened to channels and groups that were inactive for a long time. Durov did mention this in a message a few months ago that username squatters were becoming a problem.
And I was mad at first but it was equally my fault for leaving my public group inactive for more than 10 months, which is probably why the username disappeared.
It's a real problem on other social media websites too. For example, a totally inactive account on GitHub claimed an org name and it has no repositories, no information, It's totally empty and I can do nothing about it. Not even report it so that GitHub can look into it and unfreeze the username.
EDIT: I just checked the dates and the channel was inactive from November 10, 2021 to August 26, 2022. So basically 9-10 months. Previously, I wrote 3 months but time flies I guess.
And I was mad at first but it was equally my fault for leaving my public group inactive for more than 10 months, which is probably why the username disappeared.
It's a real problem on other social media websites too. For example, a totally inactive account on GitHub claimed an org name and it has no repositories, no information, It's totally empty and I can do nothing about it. Not even report it so that GitHub can look into it and unfreeze the username.
EDIT: I just checked the dates and the channel was inactive from November 10, 2021 to August 26, 2022. So basically 9-10 months. Previously, I wrote 3 months but time flies I guess.