Thanks guys on the responses/questions!

My farm runs on 3 phase 4 wire to the PDUs at 240volt, and then the PSU plugs into the PDUs.
I checked the PDUs and they are all checking in around 230-240volts at the receptacles.

I do profit switching with the Baikal BK X, so they range in power draw from 120watts to 630watts depending on which algo they are on.
The APW3++ is setup for up to 1600watts. Specs: https://www.eyeboot.com/antminer-apw3-bitcoin-power-supply.html
The APW7 is setup for up to 1800watts. Specs: https://shop.bitmain.com/product/detail?pid=00020180621115441375Ioit8oeJ06DE
I have one PSU per each miner and no PCI splitters are used.

I upgraded as the efficiency of the apw7 was 1-2% better than the apw3++ and I was able to buy the apw7 and sell the apw3 for about the same cost.
Today I went through and removed the apw7s from the baikals and re-installed the APW3++ PSUs instead.
However, all my other machines running the APW7 have not had any issues, a mix of Innosilicon D9, A9, S11 and Bitmain S9i.

I have an electrical engineer coming on Tuesday to see if we can diagnose the issue too.

Thanks for the feedback!