Hour of power

Bedtime routine, baby goes to sleep, hour later she's awake for the hour of power. She's 5 and a half months, almost crawling, and in this time she wakes, rolls to her tummy and rocks back and forth, fooling around. She still seems tired and I keep flipping her back to her back and try to settle but not much luck. I've tried pushing bedtime back by half an hour but didn't make a difference.

How do I troubleshoot this new habbit? Or is this going away once she's not stimulated by crawling?