Refund with fee amount should create a fee financial_trxn row

I have done some digging into some data issues on an upgraded site and have observed some discrepancy around how fees are recorded in a refund situation. At this stage this 'bug' has no impact on us and I'm logging this primarily to document it and to give it some visibility.

When a Contribution is created with a fee amount two rows are created in the civicrm_financial_trxn table.

However, only one is created when the contribution is edited to have a refund. Only one row would be fine if the fee were not being refunded - but you can see in the rows below the fee ($666) is recorded in the fee_amount column.

CiviCRM Financial Trxn table:
total_amount | fee_amount | net_amount | currency | trxn_id | from_financial_account_id | contribution_id |
-----------------------------------------------------------------------------------------------------------------------

Note that it's not currently possible on the form to record whether or not the fees are refunded & presumably if you edit those fields it's seen as an edit on the original contribution - so this isn't a question of whether the intent was to refund that fee - but whether the records created have internal integrity around that fee