I mean, net biased reffing in favor of one team is never overt because there are bad calls both ways. My eyeball test suggested that the Blazers benefited from a +4 bull FTA advantage compared to the spurs. There were more than 2 bad calls (2 FTA per call) in favor of the blazers, but for every bad call > 2 in favor of the blazers, there was a bad call in favor of the spurs which cancels out, hence a net rating of +4 FTA.
However, I stopped paying close attention after half time so that figure is probably not entirely accurate.
The thing is when two teams are so closely matched, a +4 bull FTA either way often exceeds the margin of victory which is disturbing, to say the least.