I thought the Mazda 3 had TPMS valves in each wheel. After a decade the battery in these MAY be failing and accordingly the valves might need replacing.

However it may be simply that the outdoor temperature is dropping (Autumn time!) and the tyre pressures are dropping a little because of this. I had a light pop up on my car that also uses a valve in each wheel. I dropped the pressures a little bit on all four tyres and reset the TPMS system. I then topped up all four tyres. This gave the TPMS monitoring a higher threshold to avoid warning lights as temperatures drop.

My 2016 Maxda6 has a passive TPMS system which relies on the abs sensors to determine relative wheel rotational speeds. I'm guessing yours might be the same. The good news is that theres no batteries to worry about. Mine has been very reliable in all the years I've had it.

Keeping the brakes clean and free of dust/dirt can help a lot (the dirt contains iron and is magnetic and can mess with the sensor). Might be worth a good powerhosing in and around the brakes to clean them out.