DDJ-SX2 Sound glitch/bug

Hi,

I have a problem with my DDJ-SX2 using Serato2.5.
I'm on an Apple Macbook pro with Big Sur.
I updated Serato +/- 10 days ago to 2.5 firmware. Until today everything worked perfectly (even with their 2.5 beta).

Since today, when I play a track trough Serato on my SX2, there is a kind of glitch, warping effect during the whole track playing. (sounds like a kind of flanger with distortion, and very light delay). Of course i've checked if there were any active effects and there is no active effect.
If I listen in my headset i don't have any problem. If I use my SX2 as an audio interface to listen to a track with the Apple app. no problem neither. 
If I use another Dj software , SX2 works good (but that is not an option, i want to continue with Serato;)).
I've been away for 2days with my laptop and I had to install Serato Lite to play with my friend's controller (Numark). When I came back I plugged back my Macbook to my usual setup and there came the bug.
I tried a lot of different things to solve this but still the same.
First of all I uninstalled Serato Lite.
Of course reboot laptop. Shut down and turn on again and again.
I tried to uninstall Serato DJ Pro and install it again, didn't work. Tried to reset the NVRAM, didn't work. Tried different usb ports, usb cables, still the same problem.
I've tried to update SX2 firmware but when I launch the updater a message tell me that the "SX2 is not connected" (but it is, and i can see it is detected in Serato). 
I hope you will be able to help me. 

Thanks a lot in advance!