Unfortunately for Blizzard, their removal of a Junkrat exploit has just led to another one being discovered. Redditor SmashRoyaleYT created a thread detailing a new exploit for the hero, and while his post has been removed, another community member helpfully posted a video of the exploit in action.
Essentially, if Junkrat uses his Concussion Mine to jump into the air and immediately presses Q, he'll make the callout for his ultimate without actually using it.
Other commenters have mentioned that jumping while hitting Q can trigger the same effect, though the timing is much harder to pull off.
It doesn't take much to think of how this could be abused. If the enemy team know a RIP-Tire is headed their way, they'll likely back off the objective and spread out in order to avoid the incoming explosives.
It'll take several precious seconds before they realize that the tire isn't actually on its way, but by that point Junkrat's team could have easily swooped in and made short work of the spread-out enemy heroes.
On top of that, Junkrat still has his ultimate in his pocket, which means he can keep using false callouts to mess with the opposition. It's not an easy exploit to pull off, but if someone can consistently make it happen they have a much higher chance of success.