Probably irrelevant to this incident, but WA's aviation forecasting is now done via either Melbourne (Southern WA) & Brisbane (Northern WA - includes YPBO & YNWN). This was a cost cutting decision by BoM to reduce the number of forecasters in Perth.
Personally, I "feel" TAF accuracy around WA has suffered as a result of this move, with the loss of local knowledge the most likely cause...