How to flush/delete items from neighbour (ARP) cache?

Question

I've had issues with some devices trying to connect on my IPv6 LAN. I had been playing around with different settings, as one tends to do at home in one's spare time. Checking the Configure -> Network -> Neighbours -> IPv6 Neighbour Cache I found a lot of "Incomplete" types. When I click the "Flush" button, nothing happens. When I try to delete individual items, nothing happens. If I disable the DHCPv6 server (on XG) and try again, nothing happens. No matter what I do, I cannot delete any entries. 
 When I check the IPv4 Neighbour Cache, it has only one item that is listed as incomplete. When I try to delete it, nothing happens. So my issue is not limited to the IPv6 entries. 
 Is there a step I'm missing to empty or delete items from the ARP cache? 
 Thanks.

FloSupport · Accepted Answer

Hi Casual_User 
 Have you tried accessing your appliance via the advanced CLI and inputting the command "ip -s -s neigh flush all". You can use "arp -n" to verify the entries in your Arp cache. See the section for connecting to the advanced shell in the following KB article . 
 Regards, 
 FloSupport | Community Support Engineer

FloSupport · Answer

Hi Casual_User 
 I'm glad to hear! Those entries should have cleared out, you could also try rebooting your appliance since it's your home network. 
 Regards, 
 FloSupport | Community Support Engineer

Evan Spangler · Answer

I am having the same issue roughly. We have a small ~100 node network (We use MSFT DC for DNS & DHCP) and it has accrued 40 pages of incomplete entries. The UI Flush function doesn't do anything. Using the advanced shell also does not work. A reboot also does not work. Sometimes the advanced shell says "flush is complete after X rounds" or "Flush not complete, bailing after X rounds" but there is no change at all in the number of incomplete entries. XG230 With 17.0.6 MR6