Pi-hole is resolving name to proper IP as proven below:
Try run below one on one of those workstations on a command line prompt to see which DNS server is answering queries:
nslookup eve-ng
If its anything other than the Pi-hole address, have a look here for proper configuration:
EDIT: You can use same tool to query Pi-hole directly:
nslookup eve-ng <PIHOLE_IP_ADDRESS>