I participated in that action so am fairly familiar with it.
However, I don't believe there is much to go on in this instance, by comparison. The FY20 report contained caveats regarding slowdown in daigou, pantry destocking, uncertainty etc. and then the Vic lockdown dragged on post-results. Hardly an open and shut case for a class action, though I agree that there would be a period in which those who purchased would rightly feel aggrieved.
Bellamy's is going back awhile now, but I do not recall any caveats, or similar extrinsic circumstances that the company could point to upon delivering a shock downgrade (seem to recall a 40% drop in one day also). It all went down in relatively normal trading conditions, whereas this was clearly not the case for A2M with border closures, lockdowns, logistic issues e.g. getting shipping containers etc. The comparison doesn't quite hold up IMO.
Anyway, good luck with it nonetheless, hope you get some answers /satisfaction out of it.
(20min delay)