SIGABRTCrash in print_exception in XF.iOS

I'm getting this error in Insights report.

It's not a reproducible issue (only 3 times in the last week).

From the call stack is very hard to understand what it's happening.

0 libsystem_kernel.dylib pthread_kill (in libsystem_kernel.dylib) + 8
1 libsystem_c.dylib abort (in libsystem_c.dylib) + 112
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
14 Foundation __NSThreadPerformPerform (in Foundation) + 372
15 CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION (in CoreFoundation) + 24
16 CoreFoundation __CFRunLoopDoSources0 (in CoreFoundation) + 264
17 CoreFoundation __CFRunLoopRun (in CoreFoundation) + 712
18 CoreFoundation CFRunLoopRunSpecific (in CoreFoundation) + 396
19 GraphicsServices GSEventRunModal (in GraphicsServices) + 168
20 UIKit UIApplicationMain (in UIKit) + 1488
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
Questionari.iOS(in 84be5b1d97303824aee4f4494fff0272)
30 libdyld.dylib start (in libdyld.dylib) + 4

Any ideas?

Thanks,

Maurizio