Hi D_Sweenie89,
Thank you for reaching out to us in our community and welcome, we are sorry to hear your facing issues with the brightness of your 360 from time to time which is only fixed by removing the HDMI cables then putting them back, I have had a look at things our end and some of your input levels are out of sync and in the red.
I will need to run further checks and possibly arrange a technician, I will send you an invite into a private chat, once received please click on the purple envelope to accept.
Regards
Paul.