NSTextAttachment image in attributed text with foreground colour

When I add an image attachment to an UITextView with a foreground colour set, the image is blanked out with the set colour:

let attrString = NSMutableAttributedString(string: rawText, attributes: [.font: UIFont.systemFont(ofSize: 17), .foregroundColor: UIColor.black])
let attachment = NSTextAttachment(image: image)
let imgStr = NSMutableAttributedString(attachment: attachment)
attrString.append(imgStr)
textview.attributedText = attrString

When I removed .foregroundColor: UIColor.black, the image is displayed correctly, but I need to be able to set the attributed text colour.

I tried to explicitly remove the .foregroundColor attribute after adding the image attachment with no luck. I also tried to remove the .foregroundColor attribute from most of the text and it still wouldn't work, only removing the attribute from the entire string works:

attrString.removeAttribute(.foregroundColor, range: NSRange(location: attrString.length-1, length: 1)) // does not work
// -------
attrString.removeAttribute(.foregroundColor, range: NSRange(location: 1, length: attrString.length-1)) // does not work
// -------
attrString.removeAttribute(.foregroundColor, range: NSRange(location: 0, length: attrString.length)) // works but no text colour

This is developed on Xcode 11.0, iOS 13. Is this a UITextView/iOS bug or an expected behaviour (which, I don't think is likely)? How do I display the image correctly with the text colour set?

It looks like there is a bug with the NSTextAttachment(image:) constructor (on iOS 13, at the time of this answer), the following image attachment construction works correctly:

let attachment = NSTextAttachment()
attachment.image = image