6 month old waking up at the same time every night

[Madt96]

My 6 month old is asleep in her cot for 8pm every night, she will sleep until 11:30pm and then just wake up crying. She's not hungry and settles as soon as we pick her up but as soon as she goes back in to her cot she starts crying/screaming, no matter how long we spend holding her she wakes up when put down. It's got to the point where I have to leave her to cry until she self settles but I worry she might disturb our 2 year old, she can be unsettled through the night sometimes and she then has a feed at around 4:30am. I will be going back to work in a couple of months and my partner does nighy shifts and I'm worrying I'll struggle with the lack of sleep, she was sleeping the night up until 5 months old. Could it be habit waking? What could I do to stop her waking at 11:30?

There's a trick I read about where you half-wake them just before their regular waking time. So say at 11 or 11.15, go in and gently move them a little bit so they rustle in their sleep but don't fully wake. It's supposed to reset them so they then won't wake. Worth a try as you've not lost anything if they wake up anyway.