Zooz Motion Sensor ZSE18 - need to be VERY close on 1 of 2 sensors

Strange that I can't seem to get one of my Zooz Motion Sensor ZSE18 to respond unless I am within 5' of the sensor.

I have two sensors, both were set up the exact same way. One is mounted in the corner by my stairs, the other on the fireplace mantle. Both were set to default sensitivity.

The one by my stairs can pick up motion on the default setting from 15-20 feet away, off axis. The one on my fireplace refuses to sense any motion until I am within 5 feet of the sensor.

I turned off the acceleration sensors and turned the sensitivity up to 6 on the mantle sensor. Both are set to clear in 10 seconds. Doesn't seem to help. The only difference between the units is that the mantle sensor is powered via USB, but not configured as a repeater. The "better" sensor is also clearing much faster than the wonky one, even though I am walking out of range of both of them.

I searched the forums and didn't find anyone with any issues on the ZSE18 regarding distance. Any thoughts?

I have a couple of these and have both set up so the USB plug is towards the bottom (or top).
Try rotating the less sensitive sensor to see if that helps. I'm not sure about the ZSE18, but generally PIR chips have a horizontal (x-axis) that is intended to sense the motion.

I unplugged the USB so it wasn't preventing me from angling the sensor exactly as I wanted. The magnetic base does make it challenging to aim "down", which is a pain in the ■■■ if you want to put the sensor up high.

Tried what you suggested, laying the sensor on its "side" and that seems to have helped a bit. Its not picking up motion at around 15'. Last night, the "good" sensor was picking up at 21-22', but this morning appears to be more finicky, not triggering until I'm around 5'.

I'm curious what the impact of lighting has on the sensor. Or if Santa Clause came late and switched my sensors as some sort of 'naughty list' joke.

Does it matter whether there's a fire going or not? Wondering if maybe the heat from the fire is affecting the sensor.