Summary
In ConnectWise PSA, a product and a General Ledger are two separate items with no relation. In QuickBooks Online a product always relates to a specific GL account. When a product needs to be created by Gozynta Mobius in QuickBooks Online, QuickBooks looks for the product and the GL account associated with it. When the product is created it is created with that GL account attached to it. In the future, any time you send over that product, it will be sent over with the original GL account that was on the product when it was created.
So if you had the product "printer" - go to "Deferred Revenue" that first time when the item was created, the next time you have an invoice for the product "printer" it will go to "deferred revenue" even if you have it listed as another GL Account in ConnectWise PSA the next time it is on an invoice.
Resolution
If you would like a product routed to a different GL Account, you will need to create a separate product and map it in the GL Account setup tables in ConnectWise PSA.