This defines the tart of a very complex series of locks I'm really unhappy
with. At the same time, there's not immediately a better solution. This also
should work without issue.
Step moved a step forward after an externally synced/added block. This created
a race condition to add the block between the sync process and the Tendermint
machine. Now that the block routes through Tendermint, there is no such race
condition.