Hypothetical function gain research?

You mean the literal proposal to put furin cleavage sites on coronavirus collected in the wild, filed for a grant in 2018, which was rejected for being too dangerous. Also, SARS-Cov-2 is the only beta coronavirus with a furin cleavage site. And if you have ever been anywhere near academic grant process, you'll know that you use a previous grant to do the next grant work, as preliminary results.

So tell me it is just a coincidence that just after writing this grant proposal in 2018 to take coronavirus in the wild and putting furin cleavage sites on them, the first beta coronavirus with a furin cleavage site turns up in the same place right next to the lab, right after they moved their sister BSL-2 lab.