Mattias Sweden, 15/02/2013 17:17:
it used to work just fine, so I assume this is a Wikimedia feature which I haven't been aware of.
Indeed. It's a feature to preserve the parity among sysops, «an intrinsic system for consensual action, reciprocal control, and prevention of abuse». https://meta.wikimedia.org/wiki/Administrator Consensus is a very important principle in Wikimedia projects.
Nemo