SMALL UPDATE ON THIS!
I've found that this bug ALSO applies to tooltips. For example, if you have a button in a controller viewport, and that button uses both an ATL transform and a tooltip, the tooltip will override the ATL for some reason, and cause it to (again, the same with the previous problem) immediately complete the animation. It seems to skip over the ease/linear arguments specifically.
I also made sure to test this without the tooltip, in which it worked fine, and with the tooltip in a regular viewport, and that, too, works fine. Not sure if this will be helpful to your debugging process or not, but I thought it to be worth mentioning.