I have a very small multi-function oven (about the size of a microwave) and for baking, the recommended setting is the "convection" one. Things bake fine in terms of taste, but muffins and cupcakes often get a sort of windswept look. The fan has clearly blown them into a lopsided shape while they're rising, but before they've set. With cupcakes, it's easy enough to trim them and hide it with icing, but not for muffins. Is there any way to avoid this effect, other than trying to bake them on a setting without the convection fan? Does this happen in larger convection ovens as well or is it just because mine is so small?
Quite often that look can be from having the temp too high on the oven. A convection oven should always be at least 25 (and some people will say up to 50) degrees cooler than a 'normal' oven. If you haven't tried it yet, knock down the temp of the oven. We used to call this 'lava tops', because basically the outside is baking and setting quickly, and then the insides pop out of the gelatinous surface, and they go in a funny direction (often the way the fan blows). I'm not saying that is the problem for sure, but if it were me, it would be the first thing I tried to eradicate the problem.