Some rough style font exhibit this behavior, because they are loaded with nodes. First, try changing the text to curves, sometimes that helps.
If not, go into the outline properties box. Try messing with the miter angles, change it to 0.0 and see if that helps. It may make it worse, but you can easily undo.
Also try various combos of the options for end caps and angles. (I'm not at a desktop right now, but its in the bottom-left corner of the box). Choosing rounded ends will usually give the best results for this problem.