Aaronrussell,
It sounds like you may need to take a look at page 7 Section 3.2 of the T8 Manual " Level Calibration ".
https://pae-web.presonusmusic.com/downloads/products/pdf/TemblorT8_OwnersManual_EN_08102014.pdf
By properly calibrating your T8 with your full range monitors, you should not experience this standby mode as you have described.
Power User Tip: Once you have matched the levels of your full-range monitors and T8, don’t use their volume controls to adjust the overall level; instead, use the volume on your audio device (computer, iPad, TV, etc.). This will ensure that your speaker levels remain matched.