Help with WAN / DHCP troubleshooting

Is sending a VendorID an ISP requirement?

Yes, it is

With my ISP, it's 2 hours to clear a lease after a device sends a VendorID. In the past, you could call their phone support to clear the lease, they now tell you to wait the 2 hours.

Already done with no luck

Just curious, if you weren't using the OpenWrt at the time, where/how did you record the packet in your first post?

Those are packets recorded in OpenWrt not in my working environment