We are testing OneWorld on our Sandbox and we are seeing that it is behaving quite differently when we try to process a sales order. Looking at the two purchase orders (SB vs prod) in SuiteQL I see some different columns in the transactionline table. Anyone know what setting might be wrong on SB that is causing this?

check if parameters on "Enable features" page are identical between SB and PROD

Yeah I agree with @Arūnas Žindžius. This sounds like someone might have accidentally changed other feature settings when enabling OW. You could check Accounting Preferences too. I think Match Bill to Receipt might be something controlled in accounting preferences.