Yup. Even within the same date, QBO is randomly mixing up the lines. 

THIS IS A BUG THAT NEEDS TO BE FIXED!

I know the work around. Just turn off the date of service. Well I want the date of service on there. Otherwise I have to type it in to every single description. I have a service company and when billing I'm entering between 300 and 600 individual service dates on my invoices. Yeah, that is getting very old. The work around is to change the description every few minutes to reflect the new service date, except some clients have multiple service dates!

You're taking my money each and every month.  FIX THIS BUG. At least let us toggle whether we want date order or entry order.