Not sure if this is a known issue or not, but it looks like if you try to inspect a resource within a non-existent stack, a stack gets autovivified:
$ rancher stacks | grep notexists
<nothing>
$ rancher inspect notexists/noservice
error notexists/noservice: Not found: notexists/noservice
$ rancher stacks | grep notexists
1st1589 notexists healthy 0 false
The expected behavior is that the ‘rancher inspect’ command to be read-only; it should not cause new stacks to be created as a side-effect of performing a (presumably read-only) query.