idk like may be 6 months or so, I have this one https://www.amazon.com/Samsung-SmartThings-F-IRM-US-2-Motion-Sensor/dp/B01IE35PCC and similar.
Don't feel too bad. People will talk up Samsung's reasonable sensor prices, but the reliability of these devices has been spotty at best for me and many others.
Edit: Do you guys not remember how horribly unreliable a lot of their sensor hardware was? https://www.amazon.com/gp/aw/d/B01IE35PCC/ref=cm_cr_arp_mb_bdcrb_top?ie=UTF8 https://www.amazon.com/dp/B0118RQW3W/ref=cm_sw_r_cp_apa_fabc_EpIRFb33YMF14