Kevin Smith has come out describing some of the scenes cut from the original Zack Snyder version of Justice League. On his show/podcast Fatman on Batman, the frequent DC TV director (and co-host of CW's DC Films Presents: Dawn of the Justice League with Geoff Johns) said that the earlier cut of the film he was shown including a tease of Superman turning evil, with visions of Darkseid.
“Superman joins the fight and teams up with the Justice League to defeat Steppenwolf, however, at one point, Steppenwolf tries to tempt Superman into joining his army,” Smith said. "This made me so f***ing angry, and we see Darkseid for the first time in Superman’s vision and we see flashes of the nightmare footage that Batman had in Batman v Superman, however, Superman snaps back out of it and delivers the final blow to defeat Steppenwolf.”
An audience member chimed in to purport they had seen this cut as well, adding to that that the visual effects for Darkseid were incomplete at that time.