It is not possible to find existing ipv6 address according to address key, so for example
:put [/ipv6 address find address=fe80::4e5e:cff:fefd:8df2/64]
returns empty set. It is same for global addresses. Similar command for neighbour discovery (/ipv6 nd prefix find prefix= ... ) works as I expect.

RouterOS version: 6.45.6