I do not feel that is likely that things will sour in the future, but I don't have a crystal ball. 

Sometimes the builders prefer to negotiate a seller subsidy or free upgrades as opposed to price, so they are not hurting their future appraisals.  

@Chad BartlettWelcome to BP, and congratulations on making the decision to invest in your future via real estate.I have written a few blog posts that may help you get started here on BP, and with your investing.

Really appreciate the recommendation. i'll be in touch with him in the near future i'll make sure to bring up your name in respect towards your reference.

You'll then have a 40% cushion should you have to foreclose in the future (worst case scenario).

We went from 40 current and future vacancies to 5 future (Sept 1) vacancies during 6 weeks of my aggressive leasing (I left to start grad school in mid July).

Given that I'm not trying to skirt the law here, to make it clear, I right now and for the foreseeable future intend to occupy ONE of the units in my three flat.

@Ryan H. the owner agreed and I wanted to know for future reference because this is a strategy that I will be using in my business.

That wouldn't affect your past 1031.the only potential "gotcha" would be in the event of a sale and future 1031. 

If so, the vinyl may be expanding too much (i.e. the window was not built correctly)(2) If all windows are doing this, is there structural problems with the building (i.e. do you see cracking in the masonry).You would not be able to screw in the vinyl as that will only cause more future damageIf all windows are doing this, I would lean towards faulty windows but hard to tell without being there to see it.