Comment 15 for bug 1950792

Figured out what made that one node different from the rest: its UEFI network boot stack had both PXE and HTTP enabled, while the others were PXE only.
After i added the kernel boot parameters, MAAS started to truncate the HTTP URI by a few characters (and now keeps doing that even if the kernel commandline options are cleared) which doesnt imapct the PXE clients but does break the HTTP ones (this node worked fine before the params were added).

For anyone stuck in this situation, the workaround seems to be to disable HTTP-based image acquisition in the system's BIOS configuration menu - PXE only on the IP stack desired will avoid the oddly truncated HTTP URI which occurs after setting kernel boot parameters.