Panasonic Inverter microwave, paint starting to flake under the ring.What can be done?

I've had several microwave ovens over the years, both painted and stainless, and this is the first time I've encountered paint peeling.I've had 20 years experience in Radar systems (which a microwave is although simplified) and 20 years experience in X-ray so I am aware of the electronic and physical properties of radiation. When I started the cavity restoration I found the paint peeled off easily in two areas in the roller path (180 and 90 degrees) there was no rust so I am assuming the problem was improper prep of the cavity during manufacture. Additionally, the paint issue caused uneven wear of the rollers on the ring so the roller ring required replacement, It has been 24 hours since the bottom of the cavity was wet sanded, cleaned with acetone and painted with QB microwave oven paint and all looks good so far. The paint and roller ring were purchased from Amazon, the sandpaper and acetone from Walmart for a total cost of $50.00 plus one hour labor. The original price of the microwave in 2017 was $172.00, today that oven will cost $249.00 to replace, so if the repair holds I will have saved about $200.00 and if not lesson learned. To anonymous who said the magnetron was defective causing the paint issue , I have to disagree. A magnetron is a tuned cavity diode and will fail in three ways assuming no metal objects were placed in the cavity and the oven operated: open filament (no cooking), shorted tube (blown fuse or failed electronics) or reduced power output due to age/use. I don't have any experience in replacing a magnetron in a microwave oven because it has not been cost effective to do so unless the oven is a high end oven.

Dont ever in future buy a microwave with a painted interior as it will always peel.......better to buy a stainless steel one.i don't know if there is a special paint you can buy but if you look on the internet you will find one.