The thing I have found is that I never realised how much eye strain I had with the bright colours of the default. When you start to get used to the dark themes, there is far less squinting at the screen, for me at least. I have green eyes and apparently they let in a lot of light. I always need sunglasses when its bright outside.
Try switching back to the default theme after using one of the dark themes for a while. You will soon see what I mean.
for me every time I load the page - or do anything whatsoever that refreshes the page/notification, the red notification number will blink somethin random, like "7", or "15", just for a second, then disappear.
i did go to my chrome settings and under the timeframe "All Time", I cleared the option for cookies/data cache as well as cache images/files
no change to the flashing, except now it lingers for an extra half second or so.
I will grab a little screen recording tonight after work. Not sure how angry the corporate A.V. gods would be at me if I tried to use a screen recorder at work. Ha. One time I tried to upload a .vbs file, inside a zip file, to AWF, and me + my manager got an automated email from I.T. within 30 seconds.