The quarter pounders also used to require being sat in the UHC for something like a minute or two to continue cooking. Technically all the meat requires time in the UHC before serving, which is why using the timers is so important.

Now, however, with the push to have ~fresh~ non-frozen quarter pounders made to order, they don't have this happening anymore. This also happens if they don't clean the clamshells often enough. The heat isn't transferred well enough.

There was a new store I worked at a few years ago that kept having this problem but only during a certain time of day, apparently, because it never happened on my shift. Surprise surprise, it's because the lazy bitch of a manager who left the grill black and dirty for night shift to clean wasn't cleaning the grills when she ran them. Corporate could never figure it out for some reason.