SAFE_POINT after click on the "Edit" button with input port "URL to in file with data"

Scenario:

1. Create some custom element with a command-line tool:
   • Set name to "test".
   • Select "python" as the external tool.
   • Add an input port with name "URL to in file with data" (leave the default type "Sequence" and the argument value).
2. Right-click on this element on the WD palette. Select "Edit".
   Current result: SAFE_POINT sometimes appear.

This issue was found during the GUITest_regression_scenarios_test_0842 GUI test execution. The error is very unstable and appears not every time. As soon as there is no idea where this problem comes from, the set of custom elements that may have caused the SAFE_POINT is provided in the attachment (extract the archive and put the "ExternalToolConfig" folder to the ".ini" folder).