Batch Action Crashes After 7,077 files?

Hi there, I have a problem with a batch process I'm trying to use to add watermarks. The "watermark" is very simple - plain grey text. However, I have 1.2 million files to process and Photoshop crashes, usually after processing 7,077 files. On average that's only about 450MB, all 1280x720 png files. These are in separate folder of about 55k each. I've tried this on two different computers. Both have drivers and Photoshop up-to-date. I have tried turning off the option to use the video card, as suggested by the troubleshooting guide. I've turned off autosave and tried adjusting the memory limit up and down. No change.

The computer does not freeze. It's just Photoshop that stops. There are no errors in the log file, and it doesn't give me a specific error. It just gives me the option to send or not send a crash report.

Please help. I don't want to have to restart this process every hour or so 170 times. If it's important my primary system is Windows 10, 32 GB memory with an Intel i7-8700k and a GTX 1080ti. I don't think the video card has anything to do with it since I turned off the option to use it to process. I'll try anything, thank you.