When doing a sharded cluster automated backup restore on 4.0.0-rc0, when we try to restart the mongos after the rest of the cluster has been restored, we get the following invariant failure in the mongos logs:

2018-05-24T19:36:22.400+0000 I SHARDING [LogicalSessionCacheRefresh] Refreshing chunks for collection config.system.sessions based on version 0|0||000000000000000000000000 
2018-05-24T19:36:22.400+0000 F - [ConfigServerCatalogCacheLoader-0] Invariant failure _shardId == _history.front().getShard() src/mongo/s/chunk.cpp 67 
2018-05-24T19:36:22.400+0000 F - [ConfigServerCatalogCacheLoader-0] ***aborting after invariant() failure

Full logs attached.

This happens for about 20 minutes (we keep retrying the start every 3 minutes or so), and then it successfully starts up.

Can try to narrow down a better repro if needed – this is from our E2E test runs, so there's not as much information as usual. If this is not sufficient information, I'll generate a repro tomorrow that we can look at more closely. kaloian.manassiev suggested I file a ticket for the failure.