Incorrect inheritance of the not existing interface global parameter.
From #1333 (closed)
Addressed in !856 (merged), note the cost is in O(log(N)) where N is the number of existing global parameters (N has a lower bound as some global parameters have a default so always exist) and of course it is a pure waste of time.
The MR is not small because getIface is heavily and incorrectly used in unit tests.