Things like this is purely developmental. Not a behavioral problem.
At certain age junctures and when they hit major "motor-skills" developmental milestones like standing-up or pulling up and what not.. it is instinctual in a baby... to then do it. It is an "impulse." They can't control their impulses. And yes, even in their sleep when they are "supposed" to be sleeping, they will "practice" their new motor-skills and do it.
And yes, they don't know yet, how to sit back down, to then lie down, and to then make themselves all into a comfy little sleep position.... again, in order to sleep. And it is repetitious. UNTIL she on her own learns how to stand-up, then sit-down, then lie-down... ALL IN sequence... she will not know how to do it on her own and it WILL tweak their sleep. When they stand-up, they then get "stuck" in that position... and don't know what "next" to do... to get themselves out of it. Normal. They don't yet have the motor-skills AND coordination working together in tandem... to problem solve this or to undo it.
So yes, until she "masters" her appendages and motor-skills and coordination of standing then sitting they lying down ON HER OWN at-will... it will happen again and again and again.... and wake her up and others. Because it is instinctual and their thoughts of then doing it... you can't exactly make her "stop" it.... unless you glue her to the crib. LOL
It WILL pass... but not yet, and not until she FULLY masters this part of her motor-skills and coordination and appendages to work all together....
Both my kids did that too as babies. And any normally developing baby will do that. So, the upside to it all is this: That your baby is developing perfectly and normally.. and she is "practicing" her skills which is normal and good... and it shows she is able to do this part of her development. HOORAY! Just take videos of it... for fond memories. That's what I did.
After she masters pulling-up and standing-up... even in her crib... then she will be onto other things. Like, knowing how to sit back down... and then knowing how to lie down again all on her own.
All the best,
Susan