Why is Apple Mail loading remote content in Spam Messages?

For a while now, likely including and pre-Big Sur, whenever I actually go through my Spam box message-by-message, when I click on one message is initially loads with the spam bar, the off yellow bar that includes "Load Remote Content" and "Move to Inbox", but then the message pane "refreshes" and loads like normal.

I am then reminded of this bug and annoyed, because I inevitably leaked information due to remote content loading.

I have 3 IMAP accounts, two Gmail based and then one third party IMAP that gets no meaningful traffic. If any spam is going to it I'd be surprised, but the significant majority of them are no doubt those coming to the Gmail-based addresses I've had and used for over a decade now. (Insert old man yelling at cloud here.)

Why does this refresh happen? Unless I explicitly remember to click outside of a message and then ⌘a to delete them, or right click them first and use that menu to delete them, is the only way I can manage spam messages, and this means messages I'm on the fence about, but ultimately have to delete, still leak information due to the afore-described behavior.

A screencapture recording the behavior

A few things to call attention to:

Quicktime Mouse Clicks are on, you can see when I click the message in the message list the "circle" that radiates outward from it. When I'm mousing over to the header information there is no click, no circle, just the ~2 seconds later refresh as I've described happening in this post. No keyboard keys were pressed at any time.

My workaround for the meantime is to not automatically load any remote content, but that's a bad solution. I'd rather that ok messages in the inbox automatically load as they're intended to be seen, and only those in junk be restricted as they initially are, before whatever happens for the junk message to "reload as normal". I always right click and junk a message that manages to make it to the inbox.

Lastly, possibly relevant preferences:

Mail Preferences -> Viewing Mail Preferences -> Junk