Is it normal? Yes, I have both the Belkin MagSafe 3-in-1 and the previous gen 3-in-1. Both seem to be cooking the AirPods rather than charging them. It’s the kind of heat you’d expext in the first few minutes of charging AirPods where both the pods and the case are completely drained - except that’s not the situation, you just needed to top up 10% or they were fully charged and you placed them there just to know where they are. Any and all scenarios seem to lead the Belkin wireless chargers to the same conclusion: this device must boil and it must boil now.
So… normal? Yup. Good? Probably not.
My AirPods Pro batteries are in surprisingly good condition after 18 months, it’s barely made a dent in the battery life — but getting the Belkin MagSafe seems to have murdered my iPhone 12 Pro battery. It was at 106% health when it arrived in November. Some 8 months and 100+ cycles later it was at 102% (according to Coconut Battery). Then I got the Belkin MagSafe in May. Battery health went into a free fall, it went from 102% to 96% in the first 3 weeks and then it’s been losing 1% every other week or so, it’s now at 88%. Same 88% as my iPhone XS which is two years older and has 350+ more cycles on it - it was only ever charged via Lightning cable and occasionally a Zens 3-in-1 charger with 10w where it barely gets lukewarm.