Luis I don't know if this is related to the same issue. For me these are two different things.
This one is about it seeing a reply which does not exist in this "timeline".
The other one you've merged is more of a visual issue, as with pressing regenerate my previous prompt stays the same, that's why my prompt shouldn't be branched, but the LLMs response should be branched. Otherwise it looks like I have edited my message (because I can see the branch buttons on my message) contrary to the fact, that my message stayed the same, but the LLM ""edited"" its message (as in regenerated).