XCUITest Screenshots not saving

I have some (very old ObjC) XCUITests, in Xcode 15.2. I recently noticed programmatic screenshots are not saving. The screenshots generated automatically by XCUITest are saving fine. This is code that used to work as expected; I do not know when it broke as I haven't had need to run this in a while.

-(void)takeScreenshotWithName:(NSString *)name {
    XCUIScreenshot *screenshot = XCUIScreen.mainScreen.screenshot;
    XCTAttachment *attachment = [XCTAttachment attachmentWithScreenshot:screenshot];
    attachment.lifetime = XCTAttachmentLifetimeKeepAlways;
    attachment.name = name;
    [self addAttachment:attachment];
    UIImage *image = screenshot.image;
    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
}

During testing I added the UIImageWriteToSavedPhotosAlbum call, to verify the code is running and the image is available - and it does. But I really don't want these images cluttering up my library.

The results are the same whether I run my tests from within Xcode, or via the command line.

I need these screenshots so I have a set in PNG format, with standardized naming, for archiving, searching, and comparisons. The automatic screenshots are in Xcode's format - useful when reviewing a single test, which isn't my use case here.