Ehh, that is weird. What do the text box next to "Current" say after you click the key? I would expect it to say "13.4" or so, as it looks like the key is not on an integer frame. You can hold shift to move keys to non-integer frames, otherwise they snap to integer frames. Another way to get keys off frames is to box select, then drag the box edge to scale the selected keys. If the key is really supposed to be on an integer frame or the "Current" text box shows an integer when at the key position, then can you email the project? contact@esotericsoftware.com

Another thing to check also might be to go back to an older Spine version and see if the behavior is different.

Whew, had me scared something was seriously wrong.