Thanks @Lindelani, its usually the same scenario in our case as well. Sometimes it also happens if after he falls asleep he wakes up because of trapped winds or tummy aches and becomes unsettled. Wasn’t sure if its normal behaviour or something to worry about, but its reassuring to hear other babies do the same.
I was also worried at first and thought it was due to something medically serious. I think it's their way of communicating. Her cues keep evolving as she grows. She also does this frantic shaking when she wants her dummy, too. One good takeaway, you are a great mommy for being super observant and vigilant!
Thanks so much @Lindelani, its good to hear this :)
My LO is also 2 months and has done the same... usually when I move from the lounge (with lights and sound) to the bedroom (dimmed lights and quiet) when we get ready for bed time. I'm not sure what the cause is but I sing a lullaby and give her my breast, which seems to calm her down and help her fall asleep.