Colour bleed

Welcome to Android Central! Sorry, but what's Prior -- is that a typo? It sounds like you're seeing the Nightlight feature, which is sort of like a bluelight filter. Go to Settings>Night Light, and adjust it there.
 
Correct, I tried to change it to Oreo but wouldn't take. I did have the Twilight app on the phone but have uninstalled it post Oreo upgrade but the red bleed still fleetingly reappears
 
It is impossible to grab a screen shot of the issue but I have been in contact with the app developer and he is aware of the issue,providing me with a number of links that discuss the issue but are beyond me! This excerpt is the most succinct.

"It’s not exactly clear why Google has made this change, as they haven’t yet provided an official explanation. My guess is it’s an attempt at improving security on Android by preventing unsuspecting users from accidentally installing apps that maliciously block or replace their status bar. Unfortunately, this change catches many perfectly legitimate applications that use TYPE_SYSTEM_OVERLAY in the crossfire."