If this is talking of Youtube videos posted here then yes that's normal especially if you're not on the best internet connection. It starts in low quality so that it can start instantly and then switches to better as the connection turns out to...
all videos on this web site (ALL) of them for a few seconds in the beginning are blurry then pops into normal view .This has been going on for ever it seems ,not a big deal but relly would like to have it right