Yes. TPU (And PETG) bond super hard to PEI because of the differential between their respective molecular sizes, among other things. Textured PEI actually reduces the bond, but it's still very strong. In fact, using flat/glossy PEI with TPU, you actually need a release agent (Like a thin layer of vegetable oil or something) on the PEI before you start your print or you'll be tearing off chunks of your bed to get the print off. Because the TPU is being squirted onto the bumpy surface, it's not actually in contact with every nook and cranny, and is really only touching about half of the PEI. This leaves tens of thousands of tiny gaps between your TPU and the PEI sheet. Alcohol is a very thin liquid, (Low viscosity) thinner than water. Flooding the PEI, a quite dense, liquid resistant material, with alcohol makes it super slick almost instantly, OTOH the TPU with it's lower density molecule tends to instantly (Temporarily) drink the alcohol up into the outermost edge of it's surface. Because of all those little gaps from the bumpy surface, the thin alcohol flows right under your print super fast. Between the two materials getting hit with the alcohol, the TPU almost automatically wants to pop right off. And like I said, this also applies to PETG if you print your first layer a little wide for extra adhesion and it gets really stuck.