Gboard: Why do I get "didn't" when I swipe "don't"?

When I swipe “don’t” in Gboard, at least 30% of the time it decides I mean “didn’t”. I just tested it, and the accuracy was shockingly bad. I’d understand if the strokes were very similar, but “didn’t” has a whole extra stroke in it compared to “don’t”. WTF, Google?