Editing a contribution linked to a membership record mistakenly modifies line_item entity

When you edit the amount of contribution associated with membership. The civicrm_line_item.entity_table is set to 'civicrm_contribution' and civicrm_line_item.entity_id = contribution id.

To replicate the above scenario
1. Create back-end membership and record payment
results
civicrm_line_item.entity_table = 'civicrm_membership'
civicrm_line_item.entity_id = membership id
civicrm_line_item.contribution_id = contribution id

2. Edit the contribution associated with the membership and change the amount field.
results
civicrm_line_item.entity_table = 'civicrm_contribution'
civicrm_line_item.entity_id = contribution id
civicrm_line_item.contribution_id = contribution id