fill a patent application and then claim that all this is your invention and your intellectual property and in this special case IH vs. Rossi additionally claim that your invention does not work, which is not only criminal but also outlandishly stupid.
It is true that one can't file for a patent, simultaneously claiming that the invention is not working.
This is not the case here.
IH had to assume that the test result is correct, when they had filed the patent application, even if this may be assessed differently today.
It's obvious, that the time course has to be considered.