Maybe this needs a completely new thread.
Some completely separate issues. Let me try and clarify:
The OP of this current thread is all about the awful congestion on the Hue Bridge caused by the last hub firmware update in September.This was pretty much fixed by your colleague @posborne (good job 
)
The osram issue I mentioned was covered below, with my long running smartthings sensors dropping out for months and investigating with help from @vlad. The root cause was due to osram bulbs messing up the mesh as they were poor repeaters as moving these off onto the hue bridge immediately resolved all of my issues overnight. I have already got the same firmware from osram which your colleague @csuk said he was testing. Clearly it is no good.
Anyway, the August update introduced another problem:
For some unknown reason you appear to have decided to not send any commands to devices reported back from the hue bridge as unreachable. Hue sometimes flag bulbs which are functioning perfectly fine as unreachable because it is unable to confirm it’s current state. However, if you use the native Hue app to control the “unreachable” devices it still works. If you any other hue compatible app it still works. If you use harmony to control an “unreachable” bulb on the hue bridge it still works.
In fact the only time it doesn’t is when you try and control it from smartthings!
Why can’t smartthings work like the native app or harmony or indeed anyone else?