I was playing Kalista just now and just realized that she now has a cap on the amount of dashes she can do once she reaches a certain attack speed. I played her on February 12th on the PBE as well and came across this same "feeling," so I assume the change must have gone through between the 10th and the 12th of this month.
In the early-game, this doesn't seem to affect Kalista that much. You likely won't have enough bonus attack speed for the cap to "kick in." However, once you have a Runaan's and a Berserker's Greaves, the cap really starts to put a hamper on the playstyle I have come to get used to as Kalista. Now you can no longer attack as fast as possible when you are dashing. There is now a windup to how fast you can attack once you have performed a dash. Simply put, this change forces Kalista players to choose between maximum DPS or (a now-capped) maximum safety through dashing once you reach more than ~1.5 attack speed.
Note that this has nothing to do with the Runaan's Hurricane windup. When I stood still and auto-attacked as Kalista, there was a clear difference in attack speed as opposed to when I was auto-attacking and dashing simultaneously. This also does not occur on live.
What is the reasoning behind this cap addition? Building attack speed doesn't feel satisfying on Kalista anymore. I had to change my build multiple times in a match. For example, I sold my Blade of the Ruined King for a Black Cleaver and even my Berserker's Greaves for Mercury's Treads because I felt like I was wasting attack speed in combat. If I wanted to play an immobile ADC with a lot of attack speed, I would play Jinx or Twitch.