If you run a command-block containing a wrong command like "/run" or anything else, it still says, the command block is triggered in the F3 block information, but it doesn't output a signal.
MC-74666
Wrong command triggers command block
Resolved
Invalid
0
It's not the command what triggers the command block, it's the redstone input.
The wrong command is run normally as every other command and spits out the generic help.