Regarding the Tradfri Hub, I also do see stability issues after a week or so.
Response becomes sluggish, up to 10s for on/off to respond, both from OH and the Ikea App.
It is not a one off as I did see the same at a second location and that was just after a few minutes with no OH involved at all.
After a Hub power cycle things are back to normal, but the problem with OH and the binding is that it stops working.
Hub and all bulbs and panels are marked as Online in HABmin, but commands do not work.
Restarting the bundle from Karaf does not help: openhab> bundle:restart "IkeaTradfri Binding"
The only remedy to regain control is $ sudo systemctl restart openhab2.service
Having played some more with Tradfri I have found these two shortcomings: (not OH related)
The phone app can only connect to 1 Hub at a time. If you need to switch Hub, the QR code needs to be scanned and the one you are leaving is forgotten.
Bulbs and panels can only have 1 remote in a group, so no ‘stairway’ function with 2 Ikea remotes is possible. Trying to pair a second remote makes it forget the first one. Using the app+Hub it is possible to move lights between groups, but not remotes. Luckily OH can fix this, using any remote