Mobile power bank to power electronic system
I figured out the problem. I am just sharing here if someone encounters similar problems in future.

I tested my platform using a power bank, however, my complete system was in power down mode except the power boost converter and LDO (so mainly power supplies were ON). This usually consumes very less current because the quiscent current of power supplies is very less in no load case. This microAmperes of current through this power supplies is in turn supplied by power bank which makes power bank think that its charge is getting leaked. So power banks have a minimum discharge current, which if detected will trigger a shutdown of power banks after a certain time (usually 30s). 

Now if I make sure that my other circuits in the platform are powered up then my whole system works perfectly with the power banks without any shutdown.

Thanks
Nik