loadNibNamed with owner silently crashes thread

With macOS 10.15 (19A471t), I'm seeing a fairly weird new crash that I have a hard time debugging.

This happens with loadNibNamed when passing an owner. Without an owner (my controller class), I can load the nib fine and show it. If I specify the owner though instead of nil, the calling thread seems to abruptly quit with no warning when debugging under Xcode.

Here's a snippet of what no longer works :

        let bundle = Bundle.main
        var topLevelObjects: NSArray? = NSArray()
        bundle.loadNibNamed(NSNib.Name(nibName),
                            owner: preferencesWindowController,
                            topLevelObjects: &topLevelObjects)

        return topLevelObjects! as [AnyObject]

I've checked that the owner is correctly initialized, it is. Also, no change reported in API https://developer.apple.com/documentation/foundation/bundle/1402909-loadnibnamed

When compiled and running (this is a screensaver), I get this crash log in console for that issue :

Crashed Thread:        0  Dispatch queue: com.apple.main-thread


Exception Type:        EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes:       0x0000000000000001, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY


Termination Signal:    Illegal instruction: 4
Termination Reason:    Namespace SIGNAL, Code 0x4
Terminating Process:   exc handler [6316]


Application Specific Information:
dyld3 mode
Crashing on exception: launch path not accessible


Application Specific Signatures:
Aerial


Application Specific Backtrace 1:
0   CoreFoundation                      0x00007fff2e5d4c63 __exceptionPreprocess + 250
1   libobjc.A.dylib                     0x00007fff63a9d06b objc_exception_throw + 48
2   Foundation                          0x00007fff30be81a0 -[NSConcreteTask launchWithDictionary:error:] + 5073
3   Aerial                              0x00000001104f1181 Aerial + 516481
4   Aerial                              0x00000001104ee964 Aerial + 506212
5   Aerial                              0x00000001104ecb5c Aerial + 498524
6   Aerial                              0x00000001104a6e9d Aerial + 212637
7   Aerial                              0x00000001104ab4db Aerial + 230619
8   AppKit                              0x00007fff2b8a9ce5 -[NSIBObjectData nibInstantiateWithOwner:options:topLevelObjects:] + 1540
9   AppKit                              0x00007fff2b8a7d17 loadNib + 401
10  AppKit                              0x00007fff2b8a72ce +[NSBundle(NSNibLoading) _loadNibFile:nameTable:options:withZone:ownerBundle:] + 693

Anyone encoutering the same issue ? Any tip on how I could track it down further ?

Thanks !