Mower deck jolts up when first engaged

[baker25]

I was doing my yearly routine maintenance of my 2015 RTZ 54" mower. I was testing out the deck after replacing the blades. When I turned on the deck, I noticed the deck raised up quite a bit and then goes back to the selected height. All wearable items are original, belts, tensioners, etc. I uploaded a video which shows it happen both with the deck lowered and then raised. I can't say that I always watched the mower deck when I activated the deck, but it seems excessive. Thoughts?

Deck jolt

 

[bertsmobile1]

They all do that
Some more then others
The tension arm & spring should take up most of it
Yours may be stuck , twisted or the pulley might be frozen .

 

[baker25]

They all do that
Some more then others
The tension arm & spring should take up most of it
Yours may be stuck , twisted or the pulley might be frozen .

Will it be obvious by looking at it?

 

[bertsmobile1]

The pulleys must rotate freely and the tension arm should swing in an arc but not flop around up & down.
Usually it is best to check with the deck off.
Wear in the tension arm pivot will be felt by trying to push & pull the tension arm which is should not do .