Faulty Motion Sensor?

So I woke up to find the lamp in the lounge was on. Checked the Smartthings app to find it was switched on by motion. It appears the motion sensor has been detecting motion all night, and as a result the lounge lamp has been switching on & off all night!

The sensor is on the wall in the lounge, and has been all year. Battery level shows good. Windows shut. No animals.

Any ideas? I assume faulty sensor?

I wouldn’t trust the reported battery levels.
Soon as the battery gets low it tends to read the levels wrong.
So I would say it’s your battery, you could test it with a multi meter if you want to be sure.

Battery. Phantom motion is always a sign to change the battery for me, even though battery report is fine. As Steve says, can’t always trust battery report.

for the Smartsense / PEQ 1st-gen motion sensors, in the USA I have occasional issues with extreme latency. Old motion reports, do not get logged until 0-8+ hours later. Then when they get logged, the programmed routines do actually run in response. We have called them phantoms or ghost events, which may have additional causes. I can see the late-expected motion reports in the recognizable pattern in the 2-3-4am period when nothing is expected.

Also I have large ambient temperature swings that do cause live motion reports.

I haven’t ever noticed a problem with low battery causing motion reports - it could happen.

Thanks for the replies. I removed the battery to reset the device, but it failed to reconnect to the hub.
Replacing the battery has enabled it to work again, so fingers crossed tonight.

Is the sensor located near a heater (or vent)?
There are a variety of things that can result in false reports.
See this faq for more ideas: