Dual cu sessions?

[bob prohaska]

Is it normal to see two cu sessions running on the same device?

I happened to run ps -aux on a Pi2 running stable/12 and noticed
root   1343   0.0  0.1   4372   1408  3  I+   16:19     0:00.02 cu -l cuaU0 -s 115200
root   1344   0.0  0.1   4372   1384  3  I+   16:19     0:00.01 cu -l cuaU0 -s 115200

One session is intentional; it provides serial access to the console of a second
machine in my Pi cluster. That I might mistakenly _start_ two sessions isn't a 
huge surprise, that it persists does seem a little odd. I'd expect "device busy".
This is a stable/12 machine, updated yesterday.

Thanks for reading and any insights....

bob prohaska