Coaches and executives of Bundesliga clubs continued to express their frustration with the video assistant referee (VAR) system during the opening weekend, with Hoffenheim coach Julian Nagelsmann calling it "a stupid period of video watching."
Even after the technology worked well at the World Cup, several games were overshadowed by what Schalke sporting director Christian Heidel called a "shambles," starting with contentious decisions in defending champions Bayern Munich's 3-1 win over Hoffenheim on Friday.
Franck Ribery earned a penalty at 1-1 when he fell as he tried to get past a tackle from Havard Nordtveit, then Robert Lewandowski was ordered to take it again when Arjen Robben encroached in the area.
Nagelsmann was particularly critical of the VAR, who was watching in Cologne, for not intervening on the initial penalty decision.
"Why the buildup to the penalty was not checked is a mystery to me," Nagelsmann told reporters after the game.
Bayern coach Niko Kovac agreed that the decision to award the penalty was not "crystal clear" and said he would not have awarded it.
The issues continued on Saturday, which was punctuated by the sight of referees consulting pitch-side monitors and talking on their headsets to the VAR.
Referee Patrick Ittrich initially sent off Wolfsburg striker Wout Weghorst before allowing him to continue in a 2-1 win against 10-man Schalke. Weghorst was shown a red card after barging into Guido Burgstaller, but the referee changed it to a yellow after it was reviewed.
Ittrich had already sent off Schalke defender Matija Nastasic after an intervention from the VAR, leading to complaints from the visiting team.
"I felt sorry for the referee today," Heidel said. "Cologne introduced the confusion. The referee would probably have done a wonderful job if the VAR hadn't intervened."
Hertha Berlin was awarded a penalty in a 1-0 win over promoted Nurnberg despite an apparent foul from Vedad Ibisevic.
There were also issues in Augsburg's victory over Fortuna Duesseldorf and Borussia Moenchengladbach's triumph over Bayer Leverkusen.
It's not always clear why the VAR is intervening, leaving referees on the pitch in the firing line -- something Bayern chairman Karl-Heinz Rummenigge does not think is fair.
"They're being left high and dry," he said.