Oily scalp after transplant. Is this normal?

Yes this is normal. There are shampoo products out there that will treat an oily scalp. Try changing products.

It is best to ask your surgeon about post operative care as each doctor has their unique regimen.  Hair follicle sometimes come with its oil gland.  It can be normal and if you are worried contact your doctor.

There is nothing to worry about. Use a good shampoo to treat the oily scalp. There are shampoos that are sold which are made for oily scalp so use these