Apple watch blinking a charging cable with red and green lightning bolt while charging

Hi John_apple_seed,

Thank you for using the Apple Support Communities! I understand you have a concern regarding your Apple Watch while charging it. I am happy to assist.

Take a look over: If your Apple Watch won't charge or it won't turn on - Apple Support which states, "When your watch is charging, the red lightning bolt changes to a green lightning bolt." It sounds like what you are experiencing is expected behavior. If your Apple Watch is not taking a charge, check out the section in that article titled, 'Get help' for some troubleshooting suggestions.

Best regards.