Comment by ptx

I looked into the issue with multiple coprocesses in bash again to make sure. While you would naturally think you could simply give them different names, it's unfortunately not supported:

https://lists.gnu.org/archive/html/bug-bash/2011-04/msg00059...

Bash will print a warning when you start the second one, and the man page explicitly says at the bottom: "There may be only one active coprocess at a time."