Photoshop quick export is saving wrong size

I'm trying to export a simple document using File > Export > Quick export as PNG. It's a banner with 240x400 but Photoshop is exporting with dimensions 212x400, so it is reducing width and I have no idea why. I never had seen something like that before.

I have a snapshot with a description about what's going on but I don't know how to fix it. See here:

Does anyone have an idea? Is there some reported bug about?