3 worker nodes were added with out any issues.
Subsequent tries to add more keep failing with the below error.
~~~
[

{''Message'': ''Unable to locate the ISO or IMG image file or folder in the network share location because the file or folder path or the user credentials entered are incorrect.'', ''MessageArgs'': ........ ''MessageArgs@odata.count'': 1, ''MessageId'': ''IDRAC.2.8.RAC0720'', ''RelatedProperties'': [''#/Image''], ''RelatedProperties@odata.count'': 1, ''Resolution'': ''Enter the correct file or folder path and credentials, and then retry the operation.'', ''Severity'': ''Informational''}

]
~~~

STEPS TAKEN:

• Verified secrets are correct, same as used for the 3 nodes that provisioned and joined the cluster.
• Verified that no virtual media was mounted.
• Tried restarting metal3 pods and trying to manually add a node again.
• Able to mount a rhel8.6 image from the bastion (since we have a centos http server defined during the IPI install), and all of the worker nodes can mount and boot from that media.

Hardware specs:
Dell R640:
2x Mellanox ConnectX-5 EN
2x Broadcom Adv. Dual 25Gb Ethernet
Intel Gold 6238R
512GB RAM
2x446.63 GB SSD
4x1787.88 GB SSD