What model/product is it 
What technology? Wifi? Bluetooth? Z...? X....? Y...
How are they powered? Batteries? Wired
Hardly can any one else with the little information you provide... It might be just the ordinary sh*tty tuya stuff which communicates over wifi but being battery powered at the same time causing heavy lags because it just takes time to establish a encrypted wifi connection (4-way-
) as well establishing the TCP/IP connection which might include some DHCP negotiations too... 
Maybe even send your motion detection ones around the world (over other peoples computers AKA cloud 
) before finally reaching your home (again) and "dropping" the detection event in HA 
But to know it you should really (try) to ask a good question and delivery at least the basic information 
This thread might be a good read for you @impy101 