Currently, if you try to assign a consumable product with lot required, it allows you to assign the move without lot. It’s true that Tryton do not permit to mark the move as done, but then I think that does not make any sense to allow to assign it.
Am I missing something?
For me, it is not related to consumable or not.
Lot are there to record what happened. It is wrong to force employee to pick a specific lot using the assignation process. So by default, the assignation does not care about the lot, but this can be activated by extending the grouping parameter of Move.assign_try to include lot. But in this case the lot would need to be filled before the assignation.