Pot sticking to induction cooktop?

I am guessing you had a bit of fluid either on the bottom of the pan or on the top of your stove. It could have been almost any fluid including water. Even though your pans can get really hot, water trapped under a pan doesn't seem to boil away very quickly, and the longer the pot sits on top of the fluid, the thinner it is pressed, thus turning into a suction problem because there is no effective fluid surface (thickness) for air to slurp in under the pot.

I cook mostly with cast iron, so the irregularity of the surface minimizes this effect a great deal.

Make sure your pot bottoms and stove surface are dry and clean. Obviously they'll still get greasy, especially during heavy cooking sessions, but try to keep the grease level to a minimum, and wipe down the stove between the burners as you go.

It is entirely possible that your pan melted a bit.

Many materials will just not warm up if you put them on an induction stove. But if you have aluminium which is thin enough, it can melt. There are people who melt alu foil on induction cooktops as a prank. I suspect that, if your pot was thin enough, or if it was layered with aluminium as the contact surface (and layered/sandwich bottoms are common in cookware), it could have heated too, and melted and fused with the cooktop.

Another way to fuse would in principle be bad enamel, if the pot itself heated enough to soften a thin layer of enamel. But this is very unlikely, since enamel has a much higher melting point than aluminium. I have used enameled pots, including cheap ones, without any problem.

This is not the only possibility, of course. As Escoce said, a burnt-on liquid can also make it stick somewhat. But if this is the case, you should be able to separate it without damaging the glass by simply pushing harder on the pot. If they are completely fused, a melted bottom is more likely.

If this is what happened, you should blame the pot, and only use pots with a "ready for induction" sign on the bottom. The only exception should be cookware for which you are sure that its bottom layer is either steel or iron. Check steel with a magnet for conductivity.

I used to work in a foundry that used induction oven to melt aluminum,zinc, and brass. I would say it was liquid suction

I had this issue too, I too believe it was the suction. Use this or something similar:

Tescoma Induktions-Adapterplatte, ø 21 cm https://www.amazon.de/dp/B00N1TFH5U/ref=cm_sw_r_wa_apa_glt_i_8N98N0TVX219CFPF5TNW?_encoding=UTF8&psc=1