The all_shard_and_config_hosts_brought_down_one_by_one.js runs multiple forced elections. Once a new primary is elected, a sync-up phase is needed in order to catch up from the old primary which could still have un-replicated changes. 
On slow variant, that phase can take over 30s as it requires a round of heart beat on any node.

Considering writes are blocked, an insertion might time out and fail. 
The goal of the ticket is to either increase the insertion timeout or lowering the catchupTimeoutMillis for the config server replica set.