Strange Characters in Emails

I've been questioned multiple times recently from users that some of the emails they receive have some strange characters in them instead of a certain punctuation mark or symbol. This is only on emails coming from outside the organization and I did recently add a rule to include a banner message on every incoming external email so I'm not sure if that's what is causing it or if it's something on the senders end. Below is an example of what I'm talking about. The top one is what it looks like in the email and the bottom is what it looks like if I click on a link in the email for a mobile friendly format. It changes the registered trademark symbol and doesn't include the dot, like on the second line. I wasn't sure if this is anything we can control or not. Thanks.

FIPCO� Compliance & Software Forum: Loan + Mortgage
October 12-13 � Stevens Point
 
FIPCO® Compliance & Software Forum: Loan + Mortgage
October 12-13 · Stevens Point