Hi radico555,
I suggest you delete the problematic rule, and then create a rule to meet your requirement.
You can follow the steps below:
1. Log in to Exchange Admin Center (EAC).
2. Click mail flow and click rules.
3. Delete the problematic rule.
4. Click New and select Apply disclaimer....
5. Click More options.
6. Under *Apply this rule if..., select The sender.
7. Click is external/internal and then select Inside the organization.
8. Finish other options and then click Save.
Thanks,
Jerry Cen