cursor_valid_after_shard_stepdown.js expects the the shard version after step down to be UNKNOWN.
However, the test doesn't account for a potential shard metadata refresh caused by the PeriodicShardedIndexConsistencyChecker and can fail.
The PeriodicShardedIndexConsistencyChecker should be disabled for this test.
- is related to
SERVER-50914 cursor_valid_after_shard_stepdown.js can fail because of an unintended metadata refresh