One thing not mentioned was... is the tube twisted inside the tire by any chance. This too can cause the tire to inflate "funny" and develop a flat spot.

best way to get the tube inside the tire is coat the tube with talcum/baby powder. real light coating by pouring bit of powder in your palm and run the tube over the palm of your hand.

Make sure the tube is not twisted when it goes in the tire.

And make sure your tire is seated properly.

smilingcat