Rejection for crash at launch occuring at line 0

I've been trying to submit my first app with SwiftUI. I've done submissions since years so I have a feeling it might be linked to the use of SwiftUI (iOS 14 only here).

My app runs well, I've no issue launching it, same when downloading it with Testflight. However, Apple tells me they're getting a crash on launch:

Code Block
Exception Type: EXC_BREAKPOINT (SIGTRAP)
0 SwiftUI 0x000000018d40ca80 0x18cf2d000 + 5110400
1 SwiftUI 0x000000018d40c87c 0x18cf2d000 + 5109884
[...]
80 SwiftUI 0x000000018d3e0e5c 0x18cf2d000 + 4931164
81 MyApp 0x00000001029057d8 main + 22488 (FakeData.swift:0)
82 libdyld.dylib 0x00000001866496c0 0x186648000 + 5824

The class FakeData is unused at runtime, it's just a class I use to populate my previews, so I'm pretty clueless about what going on here.

Example of what's inside the class:
Code Block
static let booking = Booking(id: 123, lesson: FakeData.lesson)

Does Apple use some kind of alternative automated tests that causes this that I could run to reproduce? What could cause such error?

Thanks!