Local testing fails on occasion with FetchingURLsOperationTests

When I test locally with refine test , I am sometimes seeing this. But I thought this was fully mocked well now? Did we miss something? Or does it indeed still make a request and not fully mocked?

[ERROR] Tests run: 705, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 33.75 s <<< FAILURE! - in TestSuite
[ERROR] testInvalidUrl(com.google.refine.operations.column.ColumnAdditionByFetchingURLsOperationTests)  Time elapsed: 3.174 s  <<< FAILURE!
java.lang.AssertionError: Process failed to complete within timeout 3000 expected [false] but found [true]
        at com.google.refine.operations.column.ColumnAdditionByFetchingURLsOperationTests.runAndWait(ColumnAdditionByFetchingURLsOperationTests.java:125)
        at com.google.refine.operations.column.ColumnAdditionByFetchingURLsOperationTests.testInvalidUrl(ColumnAdditionByFetchingURLsOperationTests.java:215)

[INFO] 
[INFO] Results:
[INFO]
[ERROR] Failures: 
[ERROR]   ColumnAdditionByFetchingURLsOperationTests.testInvalidUrl:215-
>runAndWait:125->RefineTest.runAndWait:392 Process failed to complete within timeout 3000 expected [false] but found [true]
[INFO]
[ERROR] Tests run: 705, Failures: 1, Errors: 0, Skipped: 0