Ann: Trading Halt, page-9

My guesses FWIW are twofold:

(1) Auditor has uncovered an issue with their work for PET
(2) Auditor has completed/submitted their work to ASX who spotted a potential issue, slapped the PAUSE, discussed with PET who, in turn, had no alternative but REQUEST A HALT in order to engage with ASX over its issues/concerns.

Either way - it is not an announcement re another CR, imminent commencement of work on a major project, expulsion from China, etc, etc.
Nonetheless, I am not only alerted but as somewhat alarmed!