Problem with availabilty and follow-on document creation

Hello all,

EBP 5.0, CCM 1.0, R/3 4.7

EBP is checking availability of the material in the shopping cart and even the stock is zero, user is getting information that material is available.

Also, system tries to create reservation and shopping cart item end in error. System is customized to create reservation if stock material is available, otherwise external procurement.

Products/materials are not replicated to EBP but imported to catalog via CSV with product_id field.

For the products on stock system is properly creating reservation.

Any hint how to solve