Thanks for reaching out to us through the QuickBooks Community, @kskadsheim-gmail.
We want to make sure you're able to import your transactions properly in QuickBooks. While QuickBooks is only a receiver of the info from Sage 50, you still need to work with their support provider. They control the information being sent to our program, including the dates of those imported entries.
We can only help you record delete the incorrect entries we receive from Sage. See this link to learn more about voiding or deleting transactions in QuickBooks Online.
If you need further assistance with this topic, post here again anytime. I'll be right here to help you out.