Official comment
Here's the problem ... you're using the mixer as an external audio device. Each channel of audio is being sent to the mixer directly. The effects are applied to the audio before it's sent to the mixer, not after. So any effect you apply to a channel will be cut with the audio when you drop the channel fader.
Unfortunately the DJM-T1 also can't be configured for INTERNAL mixer mode, so you're out of luck there.