ros 3.7 bug bug!! ARP = reply-only not effect
Ouch. So loud 
. Send message with supout.rif to support(at)mikrotik.com.
They’re reacting very fast on direct messages. They do not react on error
messages to this forum.
Stefan
We have a similar problem with proxy-arp not taking effect. For us, it only happened on interfaces with vlans configured. Took us a few back and forths with support, but they say they have figured it out and it should be fixed in 3.8.
Dave