weird photoshop problem

[nick99n]

hi guys i have this problem with any blur the more the blur the biggest this weird thing on top and left (this is 50 px gaussian blur )

i use cc for some month and this is the first time i see it (tried restarting photoshop) any ideas what's up? (yes the image is full canvas size when it is not blured)

[Hans Christian | Teri]

What exactly are you referring to? The banding?

[nick99n]

What exactly are you referring to? The banding?

[XTankSlayerX]

You may or may not have to crop the picture...??

[nick99n]

You may or may not have to crop the picture...??

the problem is i don't want to do it in the other files the blur works ok but with this one....dunno 

[Hans Christian | Teri]

So that's happening because you're trying to blur using information from outside the picture, which isn't there.

[killers993]

Look's like the bottom is messed up as well. Did you try making a new layer, and then applying the blur effect? 

[nick99n]

So that's happening because you're trying to blur using information from outside the picture, which isn't there.

no the image exceeds the canvas at bottom and right and it it snaped to the edges on the other sides 

[nick99n]

see? this is not related to the image size 

[nick99n]

i made the smart object 1920 * 1080 (canvas size) and tried again and...nothing 
i resterized the smart object (after resizing to canvas size) and nothing!
i undo and got the smart object back then made a selection of the whole image and layer via copy and it works in the copy perfectly ...wtf photoshop wtf