Google home reports error waiting for hubitat (timeout?)

I can successfully use google home voice commands to trigger hubitat switches, dimmers etc.
But google often says it "failed to reach the hubitat" even though it worked perfectly.
This gets more common if triggering light groups (eg "hey google, turn off upstairs lights")
I have quite a few lights - it can take hubitat upwards of 10s to turn off a large group - even if triggered within HE.

I'm guessing that goggle home has some kind of timeout waiting on a response from hubitat.
And presumably hubitat only responds when it has finished triggering all lights.
The same happens whether google sees them as individual lights (within a google-home room) or whether it is a single switch (a hubitat managed group).

In case its relevant, a few of my lights are Philips Hue, triggered from hubitat (not direct from goggle)
ie google home --> hubitat --> hue (via bridge)

Does anyone else experience this annoyance ? Any suggested fixes ?
Is this more a google issue ?

I have experienced the same problem a couple of times, I had to repeat the command to Google to execute it

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