Your asterisk example works OK for me. As does the blog writer's "when you do `foo()` it foos the bar".
The upside is that it's now possible to have bold passages in monospaced text. I missed that before.
The web client on Firefox works better, though: https://imgur.com/a/X53iIlm
Edit: On Chrome it's broken for me too....
I think the concern is mostly about what Slack was actually trying to achieve.