
In D365 Finance & Operations, secondary units of measure with intra-class UOM conversions work correctly in sales and purchase transactions because those processes support dual/secondary unit handling natively.
However, Inventory Movement journals primarily post inventory transactions using the inventory unit (primary unit of measure). When a secondary unit is entered manually on a Movement journal line, the system does not always automatically convert and persist the quantity correctly unless the conversion setup and item tracking configuration fully support the scenario.
Please review the following areas: