In the attempt to make binlog events appliance non blocking to the operation (to throttling, to status events), an out-of-order scenario was introduced.
This was found when experimenting with intensively written production tables (hey, I was testing with --test-on-replica so no risk to data!).

The source of problem is https://github.com/github/gh-osc/blob/master/go/logic/migrator.go#L615-L626 . Note the true as the async parameter.
Need to find a solution when binlog events are async to other events, but are streamlined in-order between themselves.