I asked about this in this post. According to a blurb I saw on the Zooz website 800 series chips will not exclude from a hub that it has not been included on. When recently adding a Zen71 I had the same issue. resetting and rebooting the Hub seem to be key, for me anyway.
As to OPs issue, have you been looking at your Z-wave details page, because if you have tried many times to include without success odds are you now have some ghost devices. If you do, get rid of those before trying again.
There is also the issue of pairing LR devices on the C8 hub, read through the thread I linked to above.
