Isn't Reyna's ult pointless with 1 opponent. I always used ult in the beginning of the round as Reyna. Am I missing some new advantage or they just noobs?

So, after some testing I've done I found out that jett's knives actually respawn when you kill the bots first time in the range but after each bot has been killed once, it wont respawn anymore. Is there a fix to this or is it currently a we...