This has happened twice now. The first time I almost thought I'd imagined it.

This is a Bosch 800 series double wall oven, about a year old. I often use the top one to cook and the bottom to hold food/heat plates for serving, on WARM.

Twice now I've had something in the top, turned the bottom one on well after the first was cooking, and much later opened the top only to find that it was at 170 (the WARM temp), despite reading the higher temp!

Tonight I took pictures of the display, showing both ovens, and a thermometer in the top oven, then turned the top off and back on and it's very clear that it's barely started to preheat.

I'll call Bosch, of course, but am wondering if anyone else has seen this. I'm not looking forward to convincing them that I'm not crazy...