The Supercars Championship leader ran as high as 11th after starting 24th, having gained most of those 13 positions with speed and some due to pit stops and incidents ahead of him.
He dropped back with a strategic decision to pit under Caution in the closing laps of Stage 1 and was running in the mid-twenties before gremlins struck the #33 Camaro for a second day in a row.
Brown initially pulled off into the infield at the exit of Turn 11, triggering a Caution during which he drove back to pit lane.
He would resume but had already dropped multiple laps and is now being shown four laps down in 36th position during the seventh Caution period (including the stage break).
The drama comes a day after a throttle issue left Brown with only around 75 percent power during qualifying, meaning he was no chance of repeating his third place in practice.
Meanwhile, Cam Waters was among those caught up in the incident which triggered the sixth yellow flag period of the race, being a victim of a tangle at Turn 11 which turned into a melee of around a dozen cars.
He is currently 23rd, among 34 still on the lead lap.
