As per the title.
This makes vJoy conflict in (at least) DCS when used together with a FFB base, because the game inputs may not be sent to the actual FFB base.
I have found a workaround if anyone is interested: uninstall and reinstall vJoy. It is still detected as FFB, but will get bumped to the last place on the device list. Now FFB input will be sent to the previous device.