Two of my devices keep disappear and re-appear in the Homekit

I’m running HA on a pi4, and there are many devices set up in HA, include 8 XiaoMi bulbs and one Xiaomi Air Purifier 2. And I mainly using HA for making devices be used in Apple Homekit since my family using a lot of Apple products.

In the total of 8 Xiaomi bulbs, 7 of them are grouped into two groups, the last one is not grouped, so they appear as total 3 lights in the Homekit (2 of them are actually 2 groups of lights in HA).
The grouped 7 bulbs work fine all the time, but the last one bulb some time it just disappears in the Homekit, then if I restart the HA, that bulb will reappear but it’ll be reset, so it’ll be in the default room and I have to re-config every automation about that bulb, it’s truly annoying.
This happens every few days.

Also, my Xiaomi Air Purifier 2 is the same, it’ll disappear in the Homekit every few days, and will be reset so I have to re-config every setting about it.

Those two devices have no problem running in the HA (I think), and they are the only two devices that have problems with Homekit, every other device just working well with Homekit from day1.
Also, those two devices usually will disappear at the same time, like in some morning, they are both suddenly disappear in the Home app on the iOS, usually they will not disappear along.
This is pretty weird and I have no clue why this is happening. I can’t re-config every automation about these devices every few days, this is not right.

Hope I can solve this problem.
Any help would be appreciated.