Bluetooth proxy connection slots can become permanently stuck, blocking all BLE connections until proxy reboot

[philbert]

During my work on the HA bluetooth stack, I encountered this very unintuitive and nasty bug which took a long time to figure out how to restore my system to working order.

Problem:

Bluetooth proxies can enter a stuck connection-slot state where all connection slots are reported as permanently occupied (slots=0/N free) despite no active connections. When this happens, Home Assistant is unable to connect to Bluetooth devices (e.g. Yale door locks) even though they are discovered, have good RSSI, and previously worked correctly.

The issue persisted across HA restarts, integration reloads, integration removals/re-additions, and can only be resolved by rebooting the affected Bluetooth proxy devices, which immediately restores normal operation.

It was difficult to trace down exactly which bluetooth proxies were causing the problems, as I suspected that it should be have been the proxies nearest the disconnected peripherals, but in my case it turned out to be my 3 Everything Presence Lite devices which are not the proxies closest to my affected devices (Yale door locks).

All 3 proxies persistently had (failures=0) (in_progress=0) (slots=0/3 free)

2025-12-16 20:31:47.806 INFO (MainThread) [habluetooth.wrappers] 
B0:44:9C:05:05:61 - LQHEW0001S: Found 4 connection path(s), preferred order: 
hci0 (FC:70:2E:0D:D7:BA) (RSSI=-81) (failures=6) (in_progress=3) (slots=3/5 free) (score=-87.09), 
tv-presence (08:A6:F7:5C:05:C6) (RSSI=-80) (failures=0) (in_progress=0) (slots=0/3 free) (score=-127), 
master-bathroom-presence-5c0574 (08:A6:F7:5C:05:76) (RSSI=-82) (failures=0) (in_progress=0) (slots=0/3 free) (score=-127), 
everything-presence-lite-931bec (08:A6:F7:93:1B:EE) (RSSI=-92) (failures=0) (in_progress=0) (slots=0/3 free) (score=-127)

Solution:

1. Enabling habluetooth.wrappers: debug is required to identify the problematic proxies.
2. Hard reboot the proxies.
3. Bluetooth connections should be restored immediately

Additional notes:

• HA 2025.12.2
• Supervisor 2025.12.3
• I currently have 10 BLE proxies enabled in my system, but it seems only 4 of them are ever listed as a valid connection path. Why?