I like @Jeff_F's proposed design solution, and it's very much in line with what I've suggested a number of times in conversations on this site about this feature. Just to put that feedback in one place, I would really like to see the options to sort by "New" (i.e. sort by post date) and sort by "Hot" (i.e. activity) to use the Reddit UI terminology as separate filters. Sorting by post activity can definitely be useful, but it isn't a replacement for being able to sort posts by date.
With this in mind, I don't really think that @LaramiePaxton's post has been "solved." This is a design choice or a bug for which there is no end user work around. As far as I know Instructure has not let us know whether the current sorting functionality is a bug or is working as intended. Either way, I view it as extremely problematic and would really like to know if it will be remedied before the enforcement date since the resorting that happens currently significantly undermines both the workflow for most instructors and the main benefit conferred by sort by new as default. If the redesign is enforced with this feature working this way, I'm going to be fielding grievances from a lot of unhappy faculty.