Empty Checkout Agreement Edit Form when Single Store Mode is enabled

[RedEnzian]

Preconditions

1. Fresh installed Magento 2.1.3
2. PHP 5.6.28

Steps to reproduce

1. Fresh Installation of Magento 2.1.3
2. Goto Stores->Terms & Conditions
3. Add new Condition
4. Try to edit Condition (works)
5. Switch to Single Store Mode
6. Try to edit Condition (does not work)
7. Add new Condition
8. Try edit new condition (does not work)

Expected result

1. Show the prefilled edit form for checkout agreements

Actual result

1. When in Production Mode there is no form displayed when clicking edit on an existing agreement
2. When in development Mode, there is an exception displayed. Attached the exception to this issue
   magento_checkout_agreement_exception.txt

[miakusha]

Hi @RedEnzian thank for report
We've created internal ticket MAGETWO-63840 to address this issue.