Transfer between Plants accounting.

Hi experts,

We are transferring a material between plants using movement type 301 (MB1B).

Material price control is 'V' in both plants, nevertheless in some transfers, the accounting document shows an amount in the G/L Account informed in the transaction AUM from OBYC.

We though this account shouldn't appear as the price control is 'V'.

Why is this account appearing? How can we find out why is this account appearing?

Thanks