If you run that on that client that couldnt resolve pi.hole via nslookup, I guess this is somehow Docker settings related.
Am not that proficient yet with Docker.
Cant help you with that ... sorry.
EDIT: Ow ps, I should have queried my other Pi that is up to date 
pi@ph5b:~ $ dig +short @10.0.0.2 chaos txt version.bind
"dnsmasq-pi-hole-v2.89-9461807"
I ran that on a machine that couldn't access http://pi.hole/admin
I dual boot so I swapped to windows so that I could rule out the machine.
Running this on a windows client expecting to have Pi-hole as its DNS.
>nslookup pi.hole
Server: UnKnown
Address: 192.168.50.3
Name: pi.hole
Address: 0.0.0.0
Depends on the docker network mode you are using.
Usually the default docker network uses 172.17.0.0/16 subnet range.
Using macvlan network, the subnet range should be the same as range used by the host.
I never saw a docker subnet using this range. I'm not saying this is wrong, but it looks unusual/unexpected.
Are you running Docker Desktop?
FYI, equivalent for Windows is (EDIT: ow you can leave out the IP if the client is configured correctly):
nslookup -class=chaos -type=txt version.bind 192.168.50.3
pi@ph5b:~ $ dig +short @10.0.0.2 chaos txt servers.bind
"127.0.0.1#5335 289931 209" "10.0.0.4#53 9086 0"
pi@ph5b:~ $ dig +short @10.0.0.2 chaos txt authors.bind
"Simon Kelley"
I shouldn't be, but that isn't to say I'm not. I have been wrong plenty of times before. The OS is ubuntu server 22.04 so I shouldn't have desktop version. I think I'm going to try wiping docker and reinstalling. I only changed one item in Pi-hole so I won't loose anything by wiping it.
Note: The only setting I changed in Pi-hole was adding a domain name for my router since Asus requires it for some reason. (After rereading my reply I expected future me to get asked that)
Is that the windows equivalent of the previous digg command?
Edit: The result is:
Server: UnKnown
Address: 192.168.50.3
version.bind text =
"dnsmasq-pi-hole-v2.89-9461807"
Yes.
Looks good.
Also mind below: