Rem Karolus is severely bugged, which caused an unexpected loss in a Double Feature draft. I had Rem Karolus on the battlefield, then my opponent cast "mirrorhall mimic" to make their own copy. After they cast their copy, they were able to destroy my creatures with direct damage spells, which should not be possible. The rules text is not written in a way that would prioritize the second instance of Rem, since it's a replacement effect rather than global. Between Gisa, Glorious Resurrector and Rem Karolus there are at least two high-impact rares in the format that do not follow their own rules text, both of which have been on the platform since last Fall without any apparent fixes. I resent having to go to Reddit to find out which (five-month-old!) cards are still bugged - at least Gisa is a little complicated, damage replacement effects have been part of Magic for 27 years.