I have been working with Salesforce for not more than 2 years, I still finding things that amaze me... but not is something that I've been struggling for a few hours now.
Every new opportunity has always need to have the same account owner or I am missing some automation in between? Every opportunity I create is changed to the Account owner if is different, reading Salesforce Docs seems that it always has been like that, or all the opportunities can have different owners even with the same Account?
If the answer is that I'm missing some automation, where can I found it? (I'm checking process builder already)