The unit of measure is being adapted (-> Help)

What causes this issue?

When processing assets, you cannot enter a quantity without a unit of
quantity. Therefore the system adapts the entry for the unit of
quantity to the entry for the quantity.
Independent of this, the system also allows for separate handling of
the maintenance level. This method allows, for example, the unit of
quantity to be specified at the level of the asset class, but the
quantity itself to be managed at the level of the asset.

How to fix this error?

Check the action carried out by the system.

Error message extract from SAP system. Copyright SAP SE.