The effect is called Macroblocking - This occurs when the encoder cannot process the amount of data within the allocated bandwidth. MPEG encoders use lossy compression that removes data during higher compression. What you are seeing is an example of the broadcaster not using a wide enough bandwidth or an incorrect compression routine for the content that they are uplinking. The Macroblock appears to be blurry blocks with reduced resolution during scenes containing rapid video changes due to movement or rapid changes in the content.
Turbosat is referring to Microblocking, which is often confused with Macroblocking. Microblocking occurs when a receiver is unable to successfully decode the signal. This could be the result of a dish out of alignment, incorrect LNBF skew, defective LNBF, bad cabling, defective decoder, etc. Microblocking errors can occur in both the audio and video decoding resulting in a stuttering audio or random blank blocks in the video.