An error occurs after filtering Tests on Test Executions/Test Plans by an URL custom field

Description

An error occurs after filtering Tests on Test Executions/Test Plans by an URL custom field.

Pre-conditions

Create a URL custom field type.

How to reproduce

1) create 2 Tests
2) create a Test Plan
3) add those 2 new tests to the test plan
4) filter Tests by the URL field
5) error occurs

Actual result/Attachments

After this error, if we refresh the page, the Tests' list is not loaded anymore, turning the Test Execution useless. ** 

Expected result

The Tests should be filtered accordingly.