I have had this issue since they were installed about 18 months ago and it has never gone away. I had the original devices replaced which made no difference.
It doesn't happen all the time, and I have not been able to recreate on demand or come up with any pattern for when it happens.
I'm hoping for a new version of these at some point in the future and that they will not have the same issue. I have not found a suitable alternative to these that also work with a standard UK rocker switch.