Synfig 1.0 changing Keyframe times

I was working on an animation which ended up being a little slower than I intended, so I tried decreasing the number of frames between keyframes, it works for two, but when I try a third, I get a pop up that says “Set Keyframe Delta: Set Keyframe: Add Waypoint: Unable to find waypoint”

Can you share the particular file?

Sorry, Here it is. I was doing it in the lesser canvas called “Butterfly”. I particularly was trying to change the keyframes at 63, 69, and 72.
ButterflyWings Banner.sifz (92.6 KB)