Installation with Kickstart file hangs when called from Packer

I have an odd issue. I’m probably going to post this elsewhere too, but I have an issue where my kickstart file works fine if I boot from an iso and type in the inst.ks manually, but when I call is from the packer-plugin-vsphere builder, the install process hangs.

The last message in the install log is:

DBG payload.manager: Updating payload thread state: DOWNLOADING_GROUP_METADATA

After that, the install hangs. This is on RHEL 9.7, by the way. Or RHEL 9.5, which I have tried too.
I’ve dropped in to the shell before it hangs and I can ping the mirror and wget files fine.

The issue seems to be related to the "repo" lines in the ks file. I have something along the lines of:

repo --name="rhel9-baseos" --baseurl=http://my-mirror-url/baseos
repo --name="rhel9-appstream" --baseurl=http://my-mirror-url/appstream
repo --name="rhel9-epel" --baseurl=http://my-mirror-url/epel

If I comment out appstream and epel mirror this works from packer, but as I said, if I take packer out of the equation and hit 'e' on the grub menu and point inst.ks to the exact same file, it works!

Puzzled.