Abrupt change in weather/clouds during flight

The problem is we really don’t know how live weather is supposed to transition. So, what is being seen could be a bug, or could be “by design”. If the former, we really need to get screenshots or videos to document what is being seen. If the latter, then you might want to vote for this Wishlist Item:

Note the comment about “rapid transitions”, which suggests that this issue has been around since at least May 2023.