In createFragmentedCollection within defragmentation_util.js, there is a write to config.collections to disable balancing on the created collection. This update means that any test using this function does not support stepdowns because writes to config collections do not support retries.

One option would be to disable these tests from stepdown suites, but if another solution is feasible (maybe disabling balancing some other way), it would be preferable to continue running the tests on stepdown suites.