Just a note from our recent jump to 7.4, but this probably applies to any version until Microsoft gets this fixed.
- System Center Operations Manager 2016 (or build 1801 still so far) has a bug with some .Net applications via IIS (so all of the IaaS servers) and the APM portion of SCOM. Here is some info in regards to this bug and how it affect SharePoint SCOM 2016 APM Linked to IIS Application Pool Failures. - MrChiyo.com it was first reported to just be an issue with .Net 2.0 sites but like the link shows can also occur with v4.0.
As far as i have seen, the SCOM agent just causes errors during the upgrade (sorry i forgot to save the logs before snapping back the install attempt) so you can either try with the NOAPM flag set to 1 like the post above says, or in my case we have just removed SCOM for the time being from our IaaS servers.
oh and also i had to revert our default tenant for vRO back to vsphere.local or vRO wouldn't start after the upgrade of the appliances. Then just set it back after the upgrade was complete.