I warped a couple of my favorite kettles several years ago and they drive me crazy on the glass top stove.
Naturally because they spin.
Then by shear accident I saw a video where a guy said the the induction stoves warped pans like carbon steel.

That's another story but today I got the wild idea to take the warp out of my two kettels.
One the big one I placed an Oak board across the bottom and whacked it a couple of times.
Low and behold the warp came right out and it's flat again.
The small one I had to whack it with my bronze hammer I made for whacking parts on my lathe.
After several whacks the warp is gone and no spinning.
The high spot was easy to see because it was shiny.
Not recommended for cast iron.
These were old magnalite kettles I've had for many years.

The reason they warped is because I forgot about them and they got extremely hot.
Way too hot like really frigging hot.

I'm an expert with a hammer so don't try this at home.

Now it's hard to get used to the darn kettles not spinning.

But the story continues.
This is about several YouTube videos I ran across about cobon steel skillets.
Something I've never thought about or knew about.
The induction cooktop.
Especially the stand alone ones for the counter.
Many have a small area where the induction takes place heating up a small area.

Here's how it happens.
If you heat metal it expands.
If you take a flat surface and heat up a small spot in the middle it will expand but the surrounding area isn't hot or expanding.
This will cause the metal to bowe up and warp.
Even worse I've heard that the cook top pulses on and off.
The cheap ones pulse at a slower rate with the on portion of the pulse being on longer.
That on pulse is full power.
The off pulse is just that, off or zero power.

If you combine the small area and the longer full power of the on pulse your going to get a warp.
This is the same with glass top stoves as well.

To remedy this you can put a metal plate on the induction top and let it take the beating heating up and put your kettle or skillet on it.
Basically a heat defuser or dampener.
But there is no such thing as a free lunch.
No matter what you do you won't get the same performance as you would a gas burner.

Next and something that sort of had me wondering.
Some of the YouTube people I watch were using the counter top induction burners on their shows.
Then they went away and they are using gas burners.
I suspect they warped their skillets or pans but didn't say anything.
Or they just didn't like the performance.