For viewless timeseries collections the creation of the default {meta: 1, time: 1} index was recently moved to DatabaseImpl::_createCollection. With this change, the index is always built when a viewless timeseries collection is created, not just via the user-facing createCollection path.

The problem is that the user may drop the {meta: 1, time: 1} index, or even re-create it using different settings (e.g. with a collation). If we are cloning a collection in this scenario (e.g. for chunk migration or moveCollection), we shouldn't create to create the index since the user may have an incompatible one.