Newly provisioned machines unable to join cluster

This is a clone of issue OCPBUGS-10372. The following is the description of the original issue:
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This is a clone of issue OCPBUGS-10220. The following is the description of the original issue:
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This is a clone of issue OCPBUGS-7559. The following is the description of the original issue:
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Description of problem:

When attempting to add nodes to a long-lived 4.12.3 cluster, net new nodes are not able to join the cluster. They are provisioned in the cloud provider (AWS), but never actually join as a node.

Version-Release number of selected component (if applicable):

4.12.3

How reproducible:

Consistent

Steps to Reproduce:

1. On a long lived cluster, add a new machineset

Actual results:

Machines reach "Provisioned" but don't join the cluster

Expected results:

Machines join cluster as nodes

Additional info: