Yes, you can cut off the damaged portion of the leaf, it won't recover and the plant will look better without it. Treat the cut edge with your cinnamon and thoroughly clean whatever you cut it with. I do that every so often to keep my plants looking neat and green. It won't heal or grow back, you can leave the good part of the leaf to do its job. If its just damage of some sort, it won't spread and if there is fungus involved that can help to contain it.

Be sure none of the leaves are under the media and that you don't get water in the crown. That will prevent crown rot in most cases.