Why is my random movement drifting to the right?

I have some basic mobs moving in a random fashion.

Using round(random(3)+1) also tried round(random(1,4))

for 1 self.Y-16

for 2 self.X+16

for 3 self.Y+16

for 4 self.X-16

but they tend to drift to the right and slightly downward, cloistering in a corner. Seams like the random roll is giving preference for 2 and 3. Should I do it differently like using floor instead of round? or some other way to not have it leaning.

Update: Floor made it worse I think.

int(random(4))+1

Thanks I'll try it

Update: looks good and seams to be working better thanks.