That then is an indicator of your cooler being the issue! What paste was used? It could also be that the base plate isn't contacting the IHS properly too as there needs to be a certain level of pressure. Idle temps?
Edit*
Just looked up the DR Slim, that does definitely look like it might not be enough to cool ADL under high stress load like Cinebench I guess.
Edit*
Just looked up the DR Slim, that does definitely look like it might not be enough to cool ADL under high stress load like Cinebench I guess.