I am not going to second guess anymore and leave it to the NowTV Tech bods to identify and resolve.
Like you mentioned the more information the forum members with the blue screen flashing can provide the quicker NowTV can see if there is a pattern and hopefully fix it ASAP.
I have the same problem since NOW tv software update. I have a NOW tv Black box and my tv is a Panasonic OLED. I have done a factory reset on the Black box which cured the problem for a while but it has returned. It occurs every 60 seconds with a momentary blue screen - audio is unaffected.
Have you temporarily tried forcing 720p under the Display settings on your box to see if that stops the intermittent blue flashing screen until NowTV fixes the issue.
I don't know if forcing 720p on the box will help or not, but worth a try if you haven't tried it already.
BTW - A cracking TV you have there 👍, would love to own an OLED TV (especially a Panasonic) but the prices are still outside my financial reach 😢.
We're sorry that you're experiencing this issue, our teams are working hard to get to the bottom of this.
To help our teams with the investigation can we ask you to provide the following infomation: