Hi @Thomas Durso,
Thank you for contacting Q&A Forum. I would like to provide my findings and proposed solution:
Use Filtering by OU Properly
Ensure the box next to SAC is explicitly unchecked and:
You click "Next" through the wizard and apply the changes.
Then force a sync using:
powershell:
Start-ADSyncSyncCycle -PolicyType Delta
If the change doesn't apply, consider doing a full sync:
powershell:
Start-ADSyncSyncCycle -PolicyType Initial
Then, search the users in sync service/connectors/AAD-onmicrosoft.com/pending export to see if any unwanted users are there.
Kindly let me know if this work for you and please let me know if you have any further questions.
If I have answered your question, please accept this answer as a token of appreciation and don't forget to give a thumbs up for "Was it helpful"!
Best regards,
Eric