Comment 2 for bug 1848556

Hi Rod,
I did try to recreate with the qemu version that you have.

$ apt install apache2 qemu-system-x86
$ qemu-img create -f qcow2 /var/www/html/test.img 1G
# local
$ qemu-img check test.img
No errors were found on the image.
# remote
$ qemu-img check http://localhost:80/test.img
No errors were found on the image.
Image end offset: 262144

Local check and remote check both work just fine.

I recognized the image that you have there and then did:
$ cd /var/www/html/
$ wget https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img
# local
$ qemu-img check bionic-server-cloudimg-amd64.img
No errors were found on the image.
16651/36032 = 46.21% allocated, 98.92% fragmented, 98.49% compressed clusters
Image end offset: 344195072
# remote
$ qemu-img check http://localhost:80/bionic-server-cloudimg-amd64.img
<hangs>

Therefore I can confirm the behavior you described.