Traveling from Como to Luzern. Confused about train seat map.

Hey everyone, I’m super confused.

I booked 2 tickets on the Trainline app. Trenitalia from Como, Italy to Luzern, Switzerland, and during booking I was shown a seat map. I very carefully selected two seats that were side by side on the right side of the carriage (Carriage 5, 2nd class). I double-checked and was sure they were together.

But now that I got the ticket confirmation, the seats are 12 and 18, which don’t seem like they’d be together... I’m so confused because the map definitely looked like they were together! Am I blind? Or did the train layout change? Was the map just wrong?

I’d really love to sit together, and also on the right side. I just want to understand how this happened and how to fix it.

Mostly just wondering if there’ll be any issues if we sit in a seat that’s not assigned to us. I heard it’s really not a big of a deal for some trains as there’s plenty of availability of seats.

Thank you!