On Linux, when not root, list command fails, blaming lack of xmldsig (unfairly)

[binaryape]

$ mdqt list
MDQT is assuming that you want to use https://mdq.incommon.org/
Please configure this using --service, MDQT_SERVICE or MDQ_BASE_URL

XML signature verification and XML validation are not available. Install the 'xmldsig' gem if you can.
Error: Cannot check a metadata file without XML support: please install additional gems

The same command works as root.
xmldsig is actually installed

[binaryape]

1. I had assumed xmldsig wasn't needed, but Nokogiri (pulled in by xmldsig) is used to extract entity IDs, so it is.
2. Can't replicate on a recent Ubuntu when gem is used manually - is this a weird side effect of Ansible?

[binaryape]

Hopefully avoiding the problem completely now, as xmldsig is always required in 0.8.0...

[binaryape]

Fixed in 0.8.0 on some Ubuntu (Ubuntu 23.04) but still some sort of haunted gem path in Ubuntu 22.04.2.
Installing nokogiri explicitly (as root) fixed it, despite Nokogiri already being there somewhere