I thought the same until Mitsuki had Snakes.I don't think so the deadlock is not necessarily a given. I think it'll skip a generation as it has done in the past. Take as an example Anko she had a snake contract but no deadlock in her generation.
It most likely will follow this logic unless Boruto and Sarada go their own routes with summonings. But I don't see Naruto teaching Sarada toads, nor do I see Sasuke being able to pass down snakes.
Even if Boruto gets hawks, that's not really as strong as the toad contract. The deadlock are obv one of the strongest summoning combinations in the series.
Considering what the series does for parallulz, it's most def happening. Unless they create a new deadlock