User not added to group chat after being selected on the "Manage members" screen

[Horupa-Olena]

Follow up: #22561 (comment)

Bug Report

Problem

This usually happens when I uncheck one user and try to add another, but it occurs randomly.
Even if the user doesn't appear in the group chat, a system message still shows that the new member was added.

Reproduction:

1. Create a group chat with 20 members
2. Go to the Manage members screen (tap "..." in the chat)
3. Remove one user from the list
4. Add a new user
5. Observe the member counter on the Group Details screen and the member list

Expected behavior

The counter shows 20 members, and the list contains 20 users.

Actual behavior

The newly added user does not appear in the group chat.

screen-20250516-115857.4.mp4

Additional Information

• Status version: nightly
• Operating System: Android, iOS