testing the Autobreaks...Landing 14L in EDDK with Autobraks to MAX. Landing on Maximal Weight without Spoilers. And breaktemp stays at 0.0 but autobreaks work very good ..ok...back track runway ..set breaks to RTO and abort takeoff 10 kts above V1 .. now breaks are really heating up. Bug!?

No, heat builds up over time. This has been discussed a lot on here

The heat doesn't really "build up", but rather it takes time for the heat to transfer throughout the brake material evenly and then reach the temperature probes. Imagine when your hands are cold and you touch something hot (e.g. food). Sometimes (if the skin of the food is dry), it takes maybe half a second or more before you feel the full extent of the heat. Next time you try this, check your brake temps after you line up and before you start the takeoff roll. By the time you have finished backtracking, the heat should have had enough time to reach the sensors.

Plus, "0.0" doesn't mean anything close to "0.0" degrees...