So I find this problem and I want to know if anyone else has it. When I am over encumbered and I try to ride a horse or use a cart my game glitches. The cart will let me get in it but wont take me to my chosen destination. Then sometimes when I use the horse instead the horse will travel with me places it shoudn't be, like inside whiterun, or half inthe ground.

You are not supposed to be able to use modes of transportation while over-encumbered. So the carriage will not move. The horse thing sounds weird, as far as I know you shouldn't be able to ride them either so no wonder it's glitchy.