One of the reasons why you might be getting very low cash verification rates is that you assigned the bank account data to the wrong accounting bank account.
While you expected this type of high verification you might be seeing quite the opposite.
When you select the wrong account to assign to bank transactions the verification results will be low as it does not have the right set of transactions to match the two data sets.
Check the Accounts screen to see which accounts you have selected to be a ERP Match Candidate.
How to avoid assigning to the wrong account
If you are unsure which account the unassigned account periods belong to, you can use the Transactions screen to review the accounting data before assignment. By restricting the Source to ERP on the right of the screen, you can investigate the accounting data and review which accounts have activity.
Restricting further by the Accounts allows you to investigate a specific account(s). Note, the Accounts that show in the filter are the ones you have selected as Visible on the Accounts screen.