Bitbucket Server v7.21.0 was showing code in Courier typeface on Fedora Silverblue 36. After some googling and digging, I was able to mitigate the issue locally by installing Roboto Mono.
Looking at the list of fonts used for code display, I see fonts by Apple, Microsoft, Google, then Ubuntu Mono and finally Courier and Monospace. Users of non-Ubuntu Linux end up with Courier by default.
Please consider removing Courier from that list. It's not a good choice for code review.