Graybeard;
Jetstar did not get a TCAS Fail, did it?
You are right, it didn't.
I was aiming more at the ALT erroneous speed correction component, and its rate of change which may have been too much for the TCAS. The problem right now is we don't know whereabouts in the 0210 minute the NAV TCAS FAULT occurred, and it could be related to a combination of the speed error correction and the zoom climb, i.e. both were heading in different directions. Or the changes occurring between valid and invalid data.
Here's a clearer copy of the
VH-EBA FDR print-out for reference.