This test has been flaky on this branch in this variant since it was committed (see BF-29482). The mechanism to wait for a moveChunk to reach a certain state is repeatedly polling $currentOp, which is inherently brittle. The test only fails in a multiversion suite between a v4.4 mongos and v5.0 mongods. 4.4 is already EOL, and 5.0 is scheduled to be EOL in October of this year. The test is also present on all other branches without issue.

Since this looks like a test only issue specific to soon to be EOL versions, the test should be disabled in this suite instead of spending time to figure out the race in the test logic.