Welcome to iRV2.
I'll try and figure the order of occurrence , from what you've posted.
When you first turn the key on , the dash lights come on , and the bulb check sequence starts as it should.
Sometimes you turn the key to crank the engine over ; all the dash lights go out and the engine won't crank over .
When you try again a short time later the engine starts as it should and the dash lights operate correctly .
First idea is a poor connection on the batteries , as the connections heat up after the first try, they make enough contact to operate .
Remove the battery cables and clean the battery terminals and inside the cable ends.
Looks clean isn't good enough !
You have to know the connections are clean.
Second possibility is an internal issue in the ignition switch , but the battery cables need to be investigated first.