We do not have a common guideline for the preferred way of dealing with typos. As pointed out by @vcvpaiva in https://github.com/UniversalDependencies/UD_Portuguese/issues/5, annotators of some treebanks (that are now converted to UD) were explicitly asked to keep typos intact, but this may not be true everywhere, and at least new, native-UD annotation efforts may benefit from knowing what is the preferred approach. I have outlined some possibilities in a document I attach to this post:

Typos.pdf