They're working on "something".
Working on pointing out that Bambu Labs has known about the issue and failed to issue a recall. They just need the failure analysis lab report to prove that it is a design/manufacturing/QA defect so they can pin the responsibility on Bambu Labs.
In the legal world, knowing about a problem and failing to fix it opens you up for punitive damages if that problem causes harm.
Typically, if an damaging event happens and the manufacturer is found responsible, then they are only liable for the damage caused (i.e. the fire damage and printer replacement).
If they are found to have known about this in advance and failed to fix the problem prior to it causing harm to the plantiff then the plaintiff can also seek punitive damage which are not limited to the damage caused and are instead a means of punishing the company for not taking responsibility and fixing the issue that they were aware of.
This is why you see lawsuits resulting from tens of thousands of dollars of damages being awarded millions of dollars.
As it turns out, it is a bad idea piss off a community of highly motivated individuals with the knowledge and technical skills to highlight your shitty business practices.