Postage labels stopped printing wysiwyg, any ideas why or how to fix?

[Sharon15]

Some of the postage labels in Shopify have stopped printing correctly (as shown in the print preview).  I've been troubleshooting this and haven't yet figured it out.  It happens in all browsers, so it's either something changed in the label coding or my printer.  Hopefully someone here also encountered this and can help me narrow it down further and maybe fix it.

I usually use Firefox, but as I said, I tried it in other browsers also and got the same thing.  I'm on Mac OS Monterrey, and keep my OS up to date.  The printer is an HP Officejet Pro 8620 and it's been a workhorse for me.  No other problems with it.  I print my labels on plain printer paper.

Okay the specific problem:  all domestic postage prints just fine, as shown in the print preview.  But international postage - both USPS and UPS labels - do NOT print as shown in the preview.  Instead all I get is a piece of the lower barcode, blown up really big, and nothing else.  I've attached a picture of a good label (on the right) and a bad one (on the left) to show you what I mean.

I'm getting around the problem right now by making a screenshot of the label, then cropping and printing the picture.  It works but it's stupid that I have to go to all that extra effort.  So.... ideas?