[Evolution] Headers don't match email in subscribed folders

[ajgringo619 <ajgringo619 pm me>]

(Linux Mint 20.1, Evolution 3.36.4)

I recently switched my main mail account to ProtonMail. Every once in a
while, I find some of my folders are displaying different emails than
the ones the From/Subject/Date view shows. I can always fix this by
unsubscribing, then refreshing my mailbox and re-subscribing.

Since ProtonMail doesn't use subfolders yet, and I'm not a big fan of
their labels, I've been using folder names like "Bus: eBay" and
"Fin:Coinbase". Could this be a source of the problem?