Some characters in emails are replaced with "=" (equal)

I am experiencing a very funny behaviour: when the system sends emails to the users, some of the characters are replaced with and equal sign, rendering the email hard to read and breaking links.

Please see the attached picture.


Welcome to ERPNext,

What you have identified may relate to this Equal sign in emails

yes that seems to be the case since we are on an Office 365 plan.

I had tried searching for previous threads but must have chosen the wrong search pattern.