Player: V10.13.16:788B9C0
Assign a lemming a blocker. Then give the blocker any permanent skills. Afterwards, hold Alt and hover it over the blocker with permanent skills. It will still say "BLOCKER 1" on the bottom-left, and will not display what permanent skills the blocker has.
For example, if you assign a blocker a climber and swimmer, then hold Alt while hovering your cursor over the blocker, it will not display "CS--- 1", on the bottom-left but will only display "BLOCKER 1".
This issue does not occur on any walking lemming.
This happens for some other skills too, not just blockers. Will look into it.
Fixed this for the next update.