Kalista and Nautilus Ult Bug [Gameplay]

I play quite a lot of Naut support and its pretty frustrating that Kalistas ult cancels my own, even after its started chasing an enemy. You cant even tell when your Kalista is about to ult so there is no way to prevent it unless your in a call with them. With Nauts long cooldown for his ult having it cancelled by your own allies is extremely frustrating and leaves you with without an ult for long time. If its cancelled you end up not having an ult for at least 3 minutes time , thats 10% of the most games. (cd from a previous ult + time not used + cancelled ult cd = 3 or more minutes without ult) I hope you can fix this soon Riot. Thanks for taking the time to read.