It appears AppCenter Beta2 has been discontinued or there is some kind of issue on AppCenter side. For now i'll disable the updates to AppCenter Beta2 so it doesn't annoy us.

You can check it for yourself if you try to enter:
https://install.appcenter.ms/users/drklo-2kb-ghpo/apps/Telegram-Beta-2/distribution_groups/All-users-of-Telegram-Beta-2

Release: PlayStore
Version: 11.9.1
Date(UTC): 2025-04-17T21:47:42+00:00

Release: Direct/Web
Version: 11.9.1 (5900)
Date(UTC): 2025-04-30T21:41:29+00:00

Release: SourceCode
Version: 11.9.1 (5900 - 289c462)
Date(UTC): 2025-04-30T22:05:36+00:00

Release: PlayStore
Version: 11.9.2
Date(UTC): 2025-04-30T22:23:46+00:00

Release: Direct/Web
Version: 11.9.2 (5901)
Date(UTC): 2025-05-01T07:33:00+00:00

Release: Direct/Web Beta
Version: 11.9.3 (59039 - 730d58e)
Date(UTC): 2025-05-02T18:20:11+00:00

Release: Direct/Web Beta
Version: 11.11.0 (59219 - 864d5b6)
Date(UTC): 2025-05-06T08:56:22+00:00

Release: Direct/Web Beta
Version: 11.11.0 (59229 - fc26262)
Date(UTC): 2025-05-06T09:26:27+00:00

Release: Direct/Web Beta
Version: 11.11.0 (59239 - 2553cb2)
Date(UTC): 2025-05-06T10:56:38+00:00

Release: Direct/Web Beta
Version: 11.11.0 (59239 - 2553cb2)
Date(UTC): 2025-05-07T06:28:15+00:00

Release: Direct/Web Beta
Version: 11.11.0 (59279 - 1e8bf9a)
Date(UTC): 2025-05-08T09:00:37+00:00

Release: Direct/Web
Version: 11.11.0 (5927)
Date(UTC): 2025-05-08T19:56:18+00:00

Release: PlayStore
Version: 11.11.0
Date(UTC): 2025-05-08T09:15:14+00:00

Release: Direct/Web Beta
Version: 11.11.1 (59299 - 4ec2b34)
Date(UTC): 2025-05-10T14:35:09+00:00

Release: Direct/Web Beta
Version: 11.11.1 (59309 - f52acbc)
Date(UTC): 2025-05-11T22:18:36+00:00

Release: PlayStore
Version: 11.11.1
Date(UTC): 2025-05-11T22:37:31+00:00

Release: Direct/Web
Version: 11.11.1 (5930)
Date(UTC): 2025-05-12T07:34:11+00:00

Release: Direct/Web Beta
Version: 11.11.1 (59319 - d52acae)
Date(UTC): 2025-05-12T07:34:17+00:00

Release: Direct/Web Beta
Version: 11.11.2 (59329 - 941b891)
Date(UTC): 2025-05-12T08:19:25+00:00

Release: Direct/Web Beta
Version: 11.12.0 (59869 - 8ca1334)
Date(UTC): 2025-05-27T21:05:25+00:00