Rocker arm shaft movement/rotation problem

[watt600rider]

Hi all, first time posting here but been following the forum as soon as I bought my TT600R!
As you can see, I don't know German so sorry for that, hope someone will still help me.

First of all, a little contribution of problem I had and how I resolved it (you can skip this part since it is unrelated to my problem, only for future searches and help) :
White smoke coming from the engine / top of exhaust pipe
As soon as I bought my TT600R, I changed the oil and cleaned + oiled the air filter, after that the problem started.
Solution was that I overoiled the air filter, and oil from air intake box would drip oil straight on the exhaust pipe causing smoke... The problem appeared mostly when I would do a full stop (Oil in airbox would the rush to the front and leak).

Now to my current problem, I added a picture of valve cover and the marked shaft / rod of the rocker arms spins forward and backwards, only a few degrees. I guess it is just rotating as the rocker arm rotates...

1.jpg

Did you had that problem and how did you resolve it and also is it dangerous to ride it like that / should I stop riding it and get it fixed?
My not the best idea would be to fill that hole with high temp engine gasket sealant, it would help it stay in place I guess..

All help / suggestions are welcome, thank you in advance!