I use Apple Homekit on my main C8 with quite a few devices. Works fine. I wanted to have a second Homekit instance for others with just a few devices. As I couldn't do that on the main hub I used a C5 with mesh connect to my C8.
On the C5 the mesh devices from the C8 cannot be used in Homekit on the C5. So I created local virtual devices on the C5 to match the C8 devices.
Then I used the Mirror Me app to mirror the C8 mesh devices to the C5 local devices. I had to do both directions so I had to use 2 mirrors for each device. For example:
IF C8 LIGHT 1 TURNS ON OR OFF THEN TURN ON OR OFF C5 LIGHT 1.
IF C5 LIGHT 1 TURNS ON OR OFF THE TURN ON OR OFF C8 LIGHT 1.
This has all worked fine for sometime. I hadn't looked at the C5 logs in a several months as didn't see a need to. Just went into that and all the mirror app devices were generating excessive hub load messages. And I had an alert that the hub was low on memory.
Other possible reason is having the mirror app go both ways was causing it to loop somewhat, as every device change would trigger one mirror app, which would change the other device and then trigger the other mirror app.
I agree it would loop, but should only loop one time. Can't imagine why that would cause and excessive hub load. That assuming the Mirror app only looks on state change and not checking every so often.
What I noticed on my C7 and C8 is that all kinds of apps will log excessive hub load messages when the free memory becomes too low. Using Rule Manager and the Hub Information Driver I now build a rule that will reboot the Hub on low memory conditions. See this thread Hubs hang after a few months' operation
Yeah I guess I did not explain that part. Once things get to a certain point of degradation random apps/drivers will starts logging hub load errors. I have seen it many times before on these forums, to solidify that theory. That's why my #1 suggestion was to just reboot the hub.
When I had the issue with the excessive hub load on my C5 it was the first time I had ever seen this in several years. And I know it had gone much longer without a reboot.
Last night I got a call from a friend, who's system I maintain, that nothing was working on his C5. I remoted in and every device had a error of excessive hub load. He only has maybe a dozen devices total.
So rebooted his hub. Status on his dashboard was not updating. I had to go into every device and do a refresh. Most of this was on Zigbee.
Kinda puzzled as to why these things are all of a sudden happening after a couple years of no problems.
