It seems that Jonathon Groff, who played King George III quite brilliantly in Hamilton, gets rather warm when he sings–which is no wonder given the weight of the costumes–and tends to sweat and get “moist,” which he exhibited in the film version of Hamilton. That was a lot of salivae.
This story about the spit and a wonderful conversation during the editing process.
A tip of the hat to ScreenRant for reporting this.