Flash broken (from commit 3f25eb50)
After upgrading to 3.33.90 on Ubuntu 19.10, gnome-screenshot's flash works only sometimes, never on fullscreen, and uses a white flash instead of black (which conflicts with the color of open windows). I fixed it by reverting to 3.30.0.
While searching for the changes, it seems commit 3f25eb50 was responsible for these (it seems the white flash was on purpose, though - I personally dislike it a lot).
Edited by teresaejunior