I thank you for reading my not-sensationalist title, as my ears are now ringing and I can't do any more work tonight.
Shift-clicking a point in ReaFIR causes the point, and connected point, to jump up or down in value.
In the .gif, I am shift-left-clicking points. Nothing more.
I just got blasted with +24db of 2khz because of this.
macOS 10.14, Retina screen if it matters.
(I still don't regret having auto-mute off)