prevention of inconsistencies is actually the reason why SAP does not allow to activate batch management, while you have stock.
Once activate, a batch number is mandatory for anything you do with this material, and since you have no batch you cannot even scrap it, not count it to zero.
Hence the only option is to remove the BM again, fix the situation and then you may set it on again if you think this would be the right approach and you would not run into other issues in a few days/weeks/months.