The issue you're experiencing with pixels forming at the edges of objects in Cocos2d could be related to how the images are being rendered or processed. One common cause of such artifacts is the use of pre-multiplied alpha (PMA). In Cocos2d, you should ensure that PMA is handled correctly. If your texture atlas is exported from Spine with PMA enabled, make sure that Cocos2d is set to handle PMA appropriately. Alternatively, you can try exporting your texture atlas from Spine without PMA and see if that resolves the issue. Additionally, check your texture settings in Cocos2d to ensure that no unwanted compression or filtering is being applied, which could also lead to such artifacts.

Another issue is texture filtering. It looks like your assets are downscaled, so multiple pixels from the source image are filtered down to a single pixel. This will also introduce these types of artifacts. Ensure you use linear filters for texture sampling in Cocos2D. I'm afraid I don't know how that is done in CocosCreator (assuming you use that). The Spine integration is maintained by the CocosCreator team, so it's best to ask them.