The steps that leads to this issue are the following:

1. Start timeseries collection creation on the replset primary node with binary 6.0
2. Stepdown happens here after creating the bucket collection but before creating the associated view.
3. A new primary of replicaset with binary 6.1 or later is elected
4. Retry the same create collection

The second create will fail with:

NamespaceExists: Bucket Collection already exists

And it will leave a bucket collection without the associated view.

The reason is that the second create operation will not find the view but it will find the bucket collection, then it will try to see if collectionOptions of the existing bucket collection match the options from the second create operation and it will fail because the validator created in 6.0 is different from the one of later versions. In fact in SERVER-68129 we added the control.count field.