Copy menu - greyed out in Preview app

I have a workflow for capturing screenshots:

1. Press Cmd+Shift+4 to capture part of the screen.
2. Click "Send to" > Preview
3. Press Cmd+Shift+A to show the annotations toolbar
4. Add some annotations onto the image – for example draw a circle around something
5. Select All, Copy
6. Paste the image into Slack or email

Since I upgraded to Ventura, step 4 doesn't work consistently. The Copy function is usually greyed out. Other times it will copy, but omits the annotations.

Here's a screenshot showing what I mean. I've selected the entire image but the `Copy` menu is disabled.

Has anyone else encountered this? Is there a fix?