Found a bug for Mercy tonight, she can no longer heal Mei whilst she is in ice block. if she is already healing Mei and if she uses ice block, then the beam is also cut off.
Also, some of the dances cannot be on moving objects, they move in whatever the direction the object is moving and then fall off the object or cancel.
Please post this again on the Overwatch forums! That is where the Overwatch developers are active and will see your report.