I have tested this now, and find that the interfacing between the host and Csound may have problems related to sample rate. Really, it would be practical if Csound/Cabbage could pick up the sampling rate of the host, and then use that (unless sr is explicitly set in the csd).
I always thought this was the way it worked, but now I tested, and see that it does not. This means that a change of sample rate in the host will make the plugin change pitch. Apparently (I am guessing here, based on what I hear), Csound produces a chunk of samples, and this chunk is used by the host as if it has the correct sample rate. This means that running at 96000, asking for a 6kHz sine tone, I get a 12 kHz sine tone.
If sr is not specified, it will run at 44100, regardless of the host sampling rate.
Tested in Reaper with the attached csd
sinetst.csd (738 Bytes)