Blocks, mainly transparents blocks like redstone and banner especially, will be an invisible model with the regular crosshair-on outline

When a place a transparent block e.g. redstone/banners, I have an almost lag-like effect, where the model does not load for a few seconds, but the crosshair-on-block outline is still there... except this world is nearly entirely lag free, with the exception of a very annoying login reload. I have also had another bug on this same snapshot, where I had this world on peaceful. I went out (this is a creative cheats world, BTW) and I found a skeleton. On peaceful. In the daylight. It stayed there for a total of over 12 hours of active gameplay before it disapeared. It also had none of the normal skeleton AI, in fact I think its bow was up, whats up with all this?