Why would the status of the rennet change if its purpose is for research? Is the rennet used for research different than the rennet used in food production?
Twisted, I assumed so, so there would be no issur even there’s kosher meat and milk, since the only issur of mixing is through bishul (unlike eating, where there’s an issur d’rabbanan to eat a mixture).
The research distinction (rd) is what makes no sense to me.