this happen to me twice so far.
first time happened several weeks back, after beat 3rd fractal, it poped up “back to lab” screen, and most of our team pressed yes, dumb us right? I thought some1 played some joke.
however tonight it happend again, same situation, but we did not press yes, so we did not return to lab, but there is NO pop up to get us to 4th fractal.
it happend at 20+ scale, at 3rd dredge fractal.
if this indeed is a bug, please fix.