QB Issue Resolution:
It’s possible that you added them as clients if you are using the QuickBooks Online Accountant account. On the other hand, if your are subscribed under the regular QuickBooks Online subscription, you might have accidentally added them as customers.
You can check your Audit Log report to check these changes. Please refer to this article to for more information: The Audit Log: What it is, how to use it.
Resolution for Issue 'All my customers and vendors are showing as my clients why?' available: Yes (Solved).
Source: Intuit Community forum.
All my customers and vendors are showing as my clients why?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.Support for Customers
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