Hi! - I have five (5) FP300s running Matter over Thread in Home Assistant, and I think I’ve got a clean single-unit defect isolated for you.
All five are on firmware 1.1.3.8, same house, same Thread network, same HA instance. Four of them honor the HoldTime attribute exactly as written. One of them ignores it completely and appears to run at roughly a 10-15 second hold no matter what I set.
Here is a full day of occupancy data from all four bathroom units, 2026-07-28, pulled from the HA history API. The “ON events shorter than HoldTime” column is the part that matters; an ON event physically cannot be shorter than the configured hold if the setting is being honored.
Unit HoldTime ON events Shorter than HoldTime Min ON Median ON Max ON
FP300-1 60 s 61 54 (89%) 17 s 30 s 87 s
FP300-2 60 s 22 0 ( 0%) 65 s 127 s 339 s
FP300-3 120 s 19 0 ( 0%) 129 s 141 s 337 s
FP300-5 120 s 29 0 ( 0%) 145 s 380 s 1155 s
FP300-2, -3 and -5 are textbook; not one ON event in the whole day fell below the configured hold. FP300-1 had 54 of 61 events below its 60 second hold, with a minimum of 17 seconds.
The result is that FP300-1 chatters badly. Six day trend on that unit, one row per day:
Date Sensitivity HoldTime On/Off transitions Total ON Longest ON
2026-07-23 high 60 s 16 6.1 min 1.0 min
2026-07-24 high 60 s 16 13.4 min 4.5 min
2026-07-25 high 60 s 70 28.4 min 3.4 min
2026-07-26 high 60 s 112 36.4 min 2.4 min
2026-07-27 standard 60 s 118 36.0 min 1.9 min
2026-07-28 standard 60 s 122 36.4 min 1.5 min
Total ON time is stable at ~36 min/day, which matches actual use of that bathroom. So the sensor is seeing the right amount of occupancy; it’s just chopping it into 30 second fragments instead of holding it.
What I have ruled out:
Connectivity - the unit has logged 100.0% uptime with zero dropouts and zero unavailable states for six straight days. Battery is 3.028 V / 100% (CR2450).
Thread mesh - the other four units on the same mesh are fine. I ran a full RF audit of the network on 2026-07-27.
Sensitivity - I dropped this unit from High to Standard on 2026-07-26 and it made no difference to the flapping (112 to 118 to 122 transitions across the change). It did shorten the longest ON, which is the opposite of helpful.
Firmware - all five units report installed_version 1.1.3.8 with no update available.
I also want to flag something on the Home Assistant side that may be masking this for other users. The HoldTime number entity HA exposes reports min 1 / max 65534, so HA accepts any value you type and reports it as applied. There is no feedback that the device didn’t take it. On this unit HA reads back HoldTime = 60 while the device is clearly running at ~10-15 seconds. If the device is ACKing the write and then not persisting it, that would explain a lot of the “I set the timeout and nothing changed” reports on this forum.
Two questions:
Is there anything I can do remotely to force this unit to re-commit the HoldTime attribute? I’d rather not reset it since that changes the device ID and breaks my automations.
If not, I think this one is a hardware/firmware fault and I’d like to start an exchange. Happy to send device ID and server region by DM, and happy to run any test firmware you want on it since I have three known-good controls sitting right next to it.
Thx!
Chad