Hi! I know this does not make sense but...

I was finishing a mix a few hours ago. As I were using plenty of plugs and was a little lazy to deactivate some so as to open the junior mastering plugs across the master fader, a strange thing happened:

At first, I had: Q10RTAS > TC MASTER X 5 TDM > Power Dither TDM > PAZ TDM

The stereo mix was not clipping or touching 0 dB. However, red lights were showing up at the Q10 RTAS with little eq. Yes, I attentuated the inputs of Q10.

Then, I decided to change for Q10 TDM and those reds were not there anymore. Then, I started to add resonalble dbs at 60 and 120 and of course some reds popped up. So why did the RTAS version showed reds and not the TDM?