Custom expense and Income accounts not showing correctly

This is an inventory item with a custom income and expense account

supplier info of our supplier

all purchase invoices look like this

However IT purchases, Custom expense account is showing sales invoices, wrong amount and nothing related to the product

Is this a bug or have I missed something

You have not illustrated any problem with the program. You defined “Laptop for hire” as an inventory item. You then purchased one laptop for hire on 28-Sep 18. It’s value was posted to Inventory on hand, where it will remain until you sell it. At that point, its cost will be transferred to IT purchases.

You did not explain this, but it seems that you are attempting to account for rental of a laptop as though it were an inventory item. Inventory items are physical goods purchased for sale or production of other goods. If you are hiring or renting a laptop, you are buying a service, and it should not have been set up as an inventory item. You should either leave the Item field blank on the purchase invoice and simply record the hire price, posting it to an expense account, or you could define the rental laptop as a non-inventory item. See https://www.manager.io/guides/7344.