SERVER-58410 removed the code which sets last applied here:

https://github.com/10gen/mongo/blob/1887b2c89ea10f24f1e1d9f08637d4af00f67700/src/mongo/db/repl/bgsync.cpp#L494

It did not remove some of the code around this, which creates an opCtx, takes a collection lock, and takes a mutex. This code is no longer useful and should be removed.