This is brilliant. 
Well, okay, perhaps not brilliant - but you’re always great at feedback and this is perfect timing. Maybe ‘opportune’ would be a better word.
You can check the moderation history of a flagged post from it’s post wrench, which will take you to its records in the review queue:
And you can also filter the review queue to pull up any handled ones using the options at the side:
The ‘default’ view that most people see is the initial ‘pending’ one with all the unhandled flags in, but there’s options in there for lots of other things too depending on what you’re looking for. I use ‘everything’ quite a lot to see what I’ve missed when I’m not here.
Could these be more intuitive? Perhaps moving the moderation history into the flag modal?