It is the normal behavior, and can't be changed programmatically. However...
It can be changed with a fairly simple hardware modification, if you're not afraid to open up the motion sensor:
And here are some additional notes by Hubitat user @SmartHomePrimer:
Hmm, I have bunches of both the Xiaomi and Aqara-branded Temp-Humidity Sensors and all of their batteries have lasted well over a year, with the one exception being an Aqara sensor I've mounted just outside my front door. I am not surprised by the shortened battery life on that one because of the colder temperatures.
Either way, the Xiaomi-branded sensor reports based on temperature / humidity changes, the same as with the Aqara one, so you wouldn't see much difference in the frequency of reporting. I honestly don't have enough data with battery life to know which of the two lasts longer given the same battery brand / age.
