Hello,
I’m seeing some blue lines on webpages on my external display, while the built in display seems to be completely fine. Also noticed red dots around darker backgrounds, like Steam and Discord.
This could be a faulty HDMI expansion card, defects in the cable, or perhaps my screen is dying.
Has anyone else encountered this problem? If so, how did you resolve it? I use my framework laptop mostly for school and light gaming, so having 2 screens to work on is very helpful for me.
EDIT: I unplugged and plugged the cable back in and it now is working properly again. 
Thank you for your time. I hope this is helpful for anyone else who notices this issue.