I'm using Stacksift 1.0.2 (5), and whenever I try to use the in-app Sparkle updates, the update itself is shown, but the "Install and Relaunch" button doesn't ever actually install and relaunch the client. The button is disabled, and the progress bar looks finished, however Stacksift does not relaunch.

I've left the app/process running for 20-30 minutes in the background while I completed other work, and it didn't come back from that.

It looks like the quarantine xattr isn't being removed from the incoming binary:

default	08:40:40.948117+1000	Stacksift	Warning: could not remove quarantine metadata from /Users/tonyarnold/Library/Containers/io.stacksift.Client/Data/Library/Caches/io.stacksift.Client/org.sparkle-project.Sparkle/Stacksift (Autoupdate).app: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" UserInfo={NSLocalizedDescription=Failed to remove file quarantine on Stacksift (Autoupdate).app.}. This may not be a problem, the update process will continue.
error	08:40:40.949326+1000	Stacksift	launch path not accessible
error	08:40:40.951189+1000	Stacksift	(
	0   CoreFoundation                      0x00000001894b0c78 __exceptionPreprocess + 240
	1   libobjc.A.dylib                     0x00000001891d90a8 objc_exception_throw + 60
	2   Foundation                          0x000000018a25e2b4 -[NSConcreteTask launchWithDictionary:error:] + 4548
	3   Foundation                          0x000000018a286d38 +[NSTask launchedTaskWithLaunchPath:arguments:] + 160
	4   Sparkle                             0x00000001021e66e0 -[SUBasicUpdateDriver installWithToolAndRelaunch:displayingUserInterface:] + 4604
	5   Sparkle                             0x00000001021fe8d0 -[SUUIBasedUpdateDriver installWithToolAndRelaunch:] + 392
	6   AppKit                              0x000000018be37d7c -[NSApplication(NSResponder) sendAction:to:from:] + 456
	7   AppKit                              0x000000018be37b78 -[NSControl sendAction:to:] + 96
	8   AppKit                              0x000000018be37a80 __26-[NSCell _sendActionFrom:]_block_invoke + 152
	9   AppKit                              0x000000018be37970 -[NSCell _sendActionFrom:] + 196
	10  AppKit                              0x000000018be3789c -[NSButtonCell _sendActionFrom:] + 104
	11  AppKit                              0x000000018be34910 NSControlTrackMouse + 1696
	12  AppKit                              0x000000018be34244 -[NSCell trackMouse:inRect:ofView:untilMouseUp:] + 160
	13  AppKit                              0x000000018be340b8 -[NSButtonCell trackMouse:inRect:ofView:untilMouseUp:] + 740
	14  AppKit                              0x000000018be3332c -[NSControl mouseDown:] + 636
	15  AppKit                              0x000000018be316b4 -[NSWindow(NSEventRouting) _handleMouseDownEvent:isDelayedEvent:] + 4384
	16  AppKit                              0x000000018bda2064 -[NSWindow(NSEventRouting) _reallySendEvent:isDelayedEvent:] + 2444
	17  AppKit                              0x000000018bda146c -[NSWindow(NSEventRouting) sendEvent:] + 352
	18  AppKit                              0x000000018bda0344 -[NSApplication(NSEvent) sendEvent:] + 2568
	19  AppKit                              0x000000018c06db78 -[NSApplication _handleEvent:] + 76
	20  AppKit                              0x000000018bc0fcd4 -[NSApplication run] + 636
	21  AppKit                              0x000000018bbe171c NSApplicationMain + 1064
	22  SwiftUI                             0x00000001a9b941b4 $s7SwiftUI6runAppys5NeverOSo21NSApplicationDelegate_pFTf4e_nAA07TestingdG0C_Tg5 + 96
	23  SwiftUI                             0x00000001aa3d7ba0 $s7SwiftUI6runAppys5NeverOxAA0D0RzlF + 220
	24  SwiftUI                             0x00000001a9f81854 $s7SwiftUI3AppPAAE4mainyyFZ + 128
	25  Stacksift                           0x0000000102108e14 Stacksift + 19988
	26  libdyld.dylib                       0x0000000189351450 start + 4
)