Unwanted changes to group text messages on iPhone and Android

Group text messages are again are making changes, dropping oeople, changing group names to old ones all without input from anyone on chst. ver aggravating! All previous threads on this have closed without advice or response.

My siblings have iPhones and one android. Several months ago changes were made to group name and participants without input. Palrtucioanrs were dropped, old names appeared then disappeared. Then it stopped. Now happening again.

[Edited by Moderator]