Comment 3 for bug 1852502

> so the approach I'm working on is just to remove the capped collection from the dump. There's actually 1 used by juju: 'tnxs.log'

the txns collection most likely will contain in-flight transactions referenced by documents in their txn-queue property, when restoring from the backup jujud will get confused and my understanding is that it won't be able to commit changes until that out-of-sync gets sorted out (something that usually make us rely on mgopurge).