NathanSweet: Unfortunately this is how rotation mixing must work. I explained it here. It would be good to include this information in the user guide, if it's not already there.
What if I want to make a set of gears, like those in a clock, if I want to control all of them by turning the first wheel. The smaller ones need to turn at different % rates for this to work in a dynamic way. There is currently no way to set this up in Spine. And all the individual cogs need to be individually animated and it will be very difficult to control speeding up or down all of them synchronously.
Please provide an alternative rotation mode/version where it's a percentage of the total rotation it's reading from. It could be a check box like how, Local or Relative are available for some transforms if legacy behavior needs to be maintained. It's already difficult to set up certain mechanics as it is without this weird rotation behavior. Version 3 had the worst rotational behavior I've seen in any 3D or 2D software to date, requiring you to use 3 keys for one 360 degree rotation. And now you are saying we can't have another bone rotate, eg 10% of source bones 720 deg = 72 deg without it jumping around. That is just plain unintuitive and non user/creative friendly, it makes certain setups impossible and will require lots and lots of extra manual work to create the same thing.