The change in WT-5150 re-introduced a data inconsistency bug. When running 10 parallel test/checkpoint processes with the configuration from WT-4750, I can easily reproduce the data mismatch seen in that ticket on current develop.
I am not able to reproduce the mismatch on WT-5150's parent changeset 2707680.
While we may want to allow LAS cleanup without drops the fix is more complex.