Print fails at perpendicular boundaries
Since you said you don't have a cooling fan, try lowering the temperature on your print head to something like 205. The strings in the first and second picture also occur more often when the print temperature is too high as well. 

The layer time gets really small at that transition, so make sure the print speed is slowing down while printing that part of the object and pausing in between those layers to allow for cooling.

It looks like the plastic is still molten and is being dragged around too me.