https://arstechnica.com/information-technology/2021/10/researcher-refuses-telegrams-bounty-award-discloses-auto-delete-bug/

Telegram patched another image self-destruction bug in its app earlier this year. This flaw was a different issue from the one reported in 2019. But the researcher who reported the bug isn't pleased with Telegram's months-long turnaround time—and an offered $1,159 (€1,000) bounty award in exchange for his silence.

Like other messaging apps, Telegram allows senders to set communications to "self-destruct," such that messages and any media attachments are automatically deleted from the device after a set period of time. Such a feature offers extended privacy to both the senders and the recipients intending to communicate discreetly.