Opening a thread with multiple unread messages expands only the last one

### What Happened?

When I receive multiple mails in one thread and open that thread only the last mail is expanded, even though all of them are unread.

### Steps to Reproduce

1. Receive multiple mails in one thread without opening that thread
2. Open that thread


(I realize, that in this screenshot this thread shows up as read, but that's because when screenshotting changed active window the thread got marked as read as if I had switched to another thread)

### Expected Behavior

All unread emails in the thread should be expanded and all read emails should be minimized.

### OS Version

6.x (Odin)

### Software Version

Latest release (I have run all updates)

### Log Output

_No response_

### Hardware Info

_No response_