@mimihuhu: Either you were checking out an old Booklet version while having just updated the Kindlet version, or vice-versa.
As far as the Kindlet version is concerned, it may require a framework restart to actually cause it to be properly reloaded. Something which is inherently part of the MRPI (or UYK, since that's a full restart) process, hence things working properly after installing the Booklet version. (Which, incidentally, also fixes the potential Booklet/Kindlet version mismatch
).