The message pinning feature is super clunky.
By creating a log entry when you pin a message, it messes up the conversation flow and makes it harder to read.
You also cannot delete the log in the message feed that says a message was pinned.
The log remains even if you unpin the message.
For instance, in the chat:
[User] [Time] Pinned a message
[Copy of the original message]
You should be able to delete this message/log, and keep the message pinned (accessible from the Pinned Messages panel)