Capacity based putway splites the primary UOM to fracrtional qty

Hi SMEs

We have R12 and WMS. The stock locators have defined with capacity. We have items primary UOMs like cases and boxes and those secondary UOM is Each. Whenever available capacity is less than putaway qty capacity(volume), Putaway rule awkwardly split into fractional qty (cases and boxes) and same is showing qty field to the warehouse putaway operators.got confused. How to arrest this issue. Capacity split should be based on primary uom not in each.

Any one have same experience would share would be great help.

Thanks in advance

Rs