Thank you for your response. I will share what I've done with the four suggestions you sent, and other things I've tried:
1. Check Wi-Fi Connection Stability
This could be at the root of the problem, but I don't know why. We switched to optical fiber network a few years ago, but the problem has only just started in the last few months. You suggested "Try moving the printer closer to your Wi-Fi router to reduce the distance or eliminate any obstructions. " The printer and router are actually very close together, and I was concerned they weren't the minimum 5 feet apart I was surprised to read about in on of the HP help pages. I don't think the positioning is the issue since it hasn't changed in years. As for overloaded network, I can't say that this happens during any sort of load. It only happens with larger print jobs, even those where it was just two pages printing 40 times where I thought the buffer would be able to hold everything it needed.
2. Reboot Your Printer and Router
Doing this has helped, but certainly is a work around and not a long term solution. After the reboot and waiting a while (like an hour sometimes), the job that stopped in the middle starts over again from the beginning, wasting more paper.
3. Update Printer Firmware
The firmware is up to date, and has been since I first saw the problem.
4. Check Printer Queue and Restart Print Spooler
There is no backlog in the queue, and the problematic jobs just show 'error printing" or similar, until they restart themselves at random times. I have cleared the queue to avoid this sometimes, and reprinted just the pages I didn't have. If we still have problems with jobs from the Windows 10 machine, I will try this restart spooler method, but the problem is also happening from Windows 11 machine.
In addition, what I've done it assign a FIXED IP ADDRESS to the printer (following instructions I found in another HP communitiy post with similar symptoms.) I have also hard-wired the Windows 10 machine to the router rather than using WiFi. I haven't had a big print job since making these changes. I hope they help, even if I don't know why this problem started.
Thanks again.