Forced rental property depreciation?

I purchased a rental home in 2015 in which I made several major improvements to over my years of ownership and did sell the single-family home this past December. Since I was always in a very low Federal tax bracket, I did not depreciate nor expense my improvement costs (over $2500 each) preferring to wait until I sold the property to have my cost basis high and therefore making my capital gain smaller)

Unfortunately, when I try to declare the capital gain on the sale, Turbo Tax forces me to declare back depreciation for the years I did not opt in for that deduction. It appears the software is artificially altering my cost basis. That would make it appear that my cost basis is lower than what it should be. Is it possible to override forcing me to take all the depreciation for the 80k worth of improvements I made over the past 10 years with my largest being nearly 34k in 2016? Am I missing something or making an error here? Thx