Nether portal bug

I am one of the beta testers, I was testing with block and new mobs, but when I created a nether portal in the overworld (gamemode creative) firstly I had to use flint and steel few times to light it up, and when I entered, the loading terain screen did not apper, and only visible thing was the void in the backround and my netehrite sword, it was there for about 10 seconds, and after that I just appered in the nether, it happend also few times when I went back to the overworld. And also there are some bugs when the game just stops for a minute or two and continues again. If youre walking it keeps walking, jumping same... I hope you fix these before the oficial launch. Thanks