I'm here to give you some additional information about this issue. To properly assist you with this question, can you provide me a screenshot of you trying to post the transfer to an expense account? This will allow me to visually look further into the problem for you so that I can determine the best solution for your business.
In the meantime, you can check out our tutorials page. It's a Community based page to help QuickBooks Online users navigate through the product and resolve issues with certain features.
I want to make sure that your concerns are addressed. I'll be waiting for your response.