There was a typo when I created the post, I don't have ':' in my actual code.
However I was able to figure it out. There are no actual error, but in some cases pega decides to open overlay in direction that is different from specified. For instance, if the field is in the very bottom of the screen overlay opens from top, even if you asked to open it from bottom, so need to keep it in mind.
Also actual values for animtionName are defined in properties pyLaunch/pyDismiss