Xray Test Execution page takes a lot of time to load when having test run custom fields

When having a test execution with more than 100 tests and more than 5 test run custom fields configured for the project it will take more than 10 seconds only to load the Test Execution View page, even before loading the test runs.

Case 1:

Project A: Test Execution - 1000 Test - no test run custom fields: 2s

Case 2:

Project B: Test Execution - 1000 Tests - 10 test run custom fields: 20s