Clipsal 500, assuming that's some car race, apparently somehow directly interferes with the match.
The fact that they have only just made/released this decision now is piss poor.
As well as that it also pisses me off that the FFA are fine with changing this fixture at the drop of a hat because of a completely separate sporting event but gave us bugger all love when it came to half our team leaving during international windows for our WC Qualifiers/friendlies.