A follow-up. I also noticed that first (fastest) ARP response seems to be picked up by the netstack and others just ignored. If we look the following picture with two ARP responses, the first from 62:16:c3 won the race.
An another thing, I wanted to know how ESXi notifies the admin from a duplicate IP address. And the answer is that only with a single line in the vmkernel.log.
2020-12-04T11:57:54.555Z cpu38:2099384)Tcpip_Vmk: 124: arp: 00:50:56:68:ef:91 is using my IP address 172.16.101.32 on vmk1!
2020-12-04T12:17:32.287Z cpu47:2099384)Tcpip_Vmk: 124: arp: 00:50:56:68:ef:91 is using my IP address 172.16.101.32 on vmk1!
That's all? No events, no alerts, nothing in GUI. I suppose this fairly common error to appear as people do type these addresses as static and hence by hand.