QB Issue Resolution:

you have QB set to recall previous transactions in company settings, uncheck it

and you are supposed to replace the expense account with the new transaction if the expense account is different

if you do not either replace that line or overwrite it, the old expense is entered yet again

Resolution for Issue 'Why do past transactions for a vendor appear when I try to enter a new transaction? I have to scroll down to a blank line in order to enter the new expense.' available: Yes (Solved).
Source: Intuit Community forum.

Why do past transactions for a vendor appear when I try to enter a new transaction? I have to scroll down to a blank line in order to enter the new expense.: 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.

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