Hi there, yes it turns out is was the timings 
An example just to elaborate: If your automation is set to activate if motion hasn’t been detected for 10 mins between 10pm and 6am, but there has already been no motion for 10 mins before 10pm, then the automation will not fire. You’ll instead need to accommodate for this situation by bringing the start time of the automation forward or using another automation solution. Annoying given this was so easy in the old app…
Here’s my new Automation which works for me, as we generally head upstairs between 9:45pm and 10:30pm. It does mean though that there will be a few occasions where the automation will not run, if we’ve already been upstairs since before 8pm for example, but scenarios like that are unlikely in my household.
Hope that helps. I’ll update my original post with a 3rd Edit.