Why does reaction wheel still provide some small amount of manual torque even when SAS only mode is on?

[ChromeDome]

It puzzles me a lot, the craft is just a probe core with a reaction wheel but it still moves with the WASD keys.

[jimmymcgoochie]

Most probe cores have their own small reaction wheels built in, if your vessel is probe core + reaction wheel then the probe core’s own RW will be providing torque with the WASD keys even if the reaction wheel is set to SAS only. Or are you saying that the vessel is only a probe core set to SAS only but it’s still working?