Along with a co-inventor, who is employed by company ABC Pty Ltd, you invent "Gadget Thing". (To be clear: you are not employed by ABC Pty Ltd.) It looks like a great, first-of-field invention with huge commercial potential.

ABC Pty Ltd files a provisional patent application with you and your co-inventor correctly identified as Inventors, but you are not privy to the filing and so remain unaware until well after the application is made public that ABC Pty Ltd deliberately recorded itself as the sole applicant (obviously a pretty stupid decision because they clearly did not own 100% of interest in the IP). This later causes problems because ABC Pty Ltd lacked standing when they filed, and the patent/application is invalidated.

Understanding that the answer will likely vary from region to region and any observations are stuck with that caveat, is it likely that ABC Ptd Ltd has done anything illegal (e.g. IP theft)? What other issues might be relevant in a case like this?