qemu 4.2 does not process discard(trim) commands 

I'm using Arch Linux with qemu 4.2 and blktrace to monitor discard commands as they are sent to the hardware.  Blktrace shows nothing as the VM is trimming the SSDs.

I downgraded to qemu 4.1.1 and blktrace shows lots of discard commands as the VM is trimming.

Kernel version is 5.5.4.

Attached is the libvirt xml.