Broadcom NPAR and Aruba CX6400 switch, server IP unreachable by some clients?

Has anyone experienced difficulty using Broadcom's NPAR feature, perhaps with an Aruba CX 6400 series switch, or Windows Failover Cluster? This is my first time working with NPAR so I'm not schooled on pitfalls or gotchas.

Here's the problem. Using NPAR on two servers to split up a 25G link on each into several different roles (separate vlans.) Some of client machines can't reach one server's IP, while other client machines on the same network have no problem talking to both server's addresses.

I thought maybe an ARP table was messed up, so everything got rebooted, switches, computers, etc. No change.

I had started to type a novel to explain this problem but who has time to read a novel.

Server: Two matching config HPE DL325 G10+ v2 with two HPE Broadcom NetXtreme E-Series dual port 10/25G card

Switch: HPE Aruba CX6405 switch running firmware FL.10.06.0140 (August 2021), ports for the servers are configured as trunks, with vlan 1 native, all vlans allowed. Clients talk to the servers over vlan 101.

Software: Windows Failover Cluster on Server 2016, latest updates, latest HPE service pack for drivers / firmware