I cannot verify DVD when burning image with Toast 18 PRO. I have loaded a disk image into Toast and started a disk burn. The disk appears to write fine. Then verification starts. At about 30% of the way, Toast hangs and has to be force quit. Inspecting the written disk, it appears fine, however, the 16X drive and 16X media only write at a 5X rate. Any idea why the hang. I have tried several times. It is a USB 3 B to USB A cord into an Apple USB A to Thunderbolt dongle that I am using on a 2017 MacBook Pro. CD burning is fine. The drive that will not work properly is an external drive with an LG mechanism a 4K cache HL-DT-ST BD-RE WH16NS40. I also have a portable LG HL-DT-ST BD-RE WP50NB40 with no cache that works perfectly. The more expensive drive is having a problem and I am at a loss to understand what is wrong.