Funky Hydraulics

[Bonaro]

I have a L275 with a L1730 FEL. The FEL is connected directly to the hydraulic ports on the tractor and no other attachments.
Today I was cleaning some rough areas with my back blade. I put the loader in float and was dragging backward and since the back blade rides low, I reached down to lift it all the way up with the draft control. When I pulled the DC all the way up the FEL bucked started lifting...while in float.
What the heck is going on here?

 

[Roadworthy]

The only time I ever experienced that issue I found one of the loader hydraulic lines needed tightened. It was on a hose I had just replaced. I tightened the fitting and the problem magically disappeared.

 

[Bonaro]

The only time I ever experienced that issue I found one of the loader hydraulic lines needed tightened. It was on a hose I had just replaced. I tightened the fitting and the problem magically disappeared.

weird...I cant get my head around why this would happen. I dont have any leaks and my hoses are tight