North Midmaer Way: Glicht in Witch quest

Title: North Midmaer Way: Witch quest broken

Reproduction Rate: not sure, I see no way restart a quest

Blocker: No, Exit and relog "solves" the problem

Details:
During task "Prime 4 Sprinklers then Use Sprinkler Control Valve" of the witche's questline I primed the four sprinklers and tried to use the valve at the well. It is not possible. The mouspointer does not change (remains white) and no tooltip appears. Double clicking on the valve has no effect, neither does pressing the "e" button while aiming at the valve. To be sure that this is caused by missing a sprinkler, i checked them again. On all four a message telling me the sprinkler is already primed appears when i double click them.

When moving the mouse poiner on the well itself, away from the valve, the usual funktiuon to fill a bucket with water is available (mouse pointer turns green and tooltip appears) and working (clicking causes the bucket filling animation).

After exiting the client and logging on again I was able to operate the valve.

Steps to Reproduce:
Play the witches quest until the task "Prime 4 Sprinklers then Use Sprinkler Control Valve" is given. Prime the sprinklers, go to the well and try to use the valve.
If it doesn't work, exit the client and relog, try again.

User Specs: PC, Win 7, 64bit, game version 50, subscribed user