Failure Injection with SITL not working as expected

Hello everyone,
currently I’m working with the PX4 Autopilot as it is part of a university course. We are using SITL simulation with jmavsim to explore how different failures express themselves in the logs.
Today I wanted to inject failures with the ‘failure’ command over the shell (eg. failure gps off). While reading the docs for it it seem that there is a wide variety of possible failures. In reality only a handfull actually worked (See pictures). My current guess is that most of the failures are not implemented right now. Can someone confirm this?
My second question is if someone know another / better way to inject failures into a simulation?

Thanks for your answeres.