Hello,
The DOZEN UOM type you may have configured as "Bigger than the reference uint of measure", and also the may defined one Bigger Ratio too.. So that when you try to define the purchase UOM as Dozen and Unit of Measure as Unit, then Odoo will convert the qty during the time of purchase, the formula will be (1*(this unit)=ratio*(reference unit). So thats what you had get that kind of output.

As Balagopal R said like , you have to set up the same UOM for Purchase Uinit of measure and Unit of Measure on the product which you want to make purchase. Try this way, hope it will works..

Thanks for all the solutions.

Hi Wanna,

Odoo allows to receive in same UOM but in that case purchase UOM and UOM at product must be same (In this case Dozen) .

https://drive.google.com/file/d/1tuAUnyyLqHOl5-rPPggPMEjqMRl52gN2/view?usp=sharing