out of 5 that i sent back 4 very simular issues twice 2 in row (same prescription chemist here gets gives 2 a time) bad batch imo likely. abbotts usually great at replacing malfunctioning sensors just a shame about parcel force prefered method of courier for them. they've asked each and everytime for sensors to get sent back, dont even need to call them theres a form can fill out:
https://www.freestyle.abbott/uk-en/support/sensor-support-form.html would be nice if they gave tracking id in remote area here can take several days although they pay for 24 hour shipping (hopefully they recover the swift deliverly price). had 5 failures at various times one never functioned except initial warmup before lo then switching off. not too bad though 5 returns within 10 months