Hi,
Did you use the last Service Pack for ProLiant (Gen8 and after) iso to update all firmware/drivers of your server's devices ? Maybe it can improves the behaviour with ESXi 6.7
I recently had issues with new ProLiant Gen10 and ESXi 6.7 and the Service Pack resolved some stuffs.
Be careful to download the Service Pack for Pre Gen 8 if you have Gen 8 or less, or Gen9plus if you have Gen 9 or Gen 10.
Here's the link for the latest SPP for Gen 9Plus version : Service Pack for ProLiant | Hewlett Packard Enterprise
Here's the link for the Gen8 version : Service Pack for ProLiant | Hewlett Packard Enterprise