Learn English – A less hostile word that can replace “violation”

I am working with a large open source software project whose code base has to be GNU Public License version 2 (GPLv2). We have to make sure that the "stuff" that goes into the project from our volunteer contributors has a license that is compatible with the project. I am setting up an issue tracker to track potential problems. The most severe problems are currently tagged with the word "Violation" and the guide for contributors explains it like this:

Violation: This means that the problem with your contribution is regarded as unequivocal and that immediate action to repair the situation is requested. A contribution with a public license that is not compatible with the GPLv2 will typically have this component, as will a contribution that illegally bundles files belonging to a 3rd party (i.e. bundles such files without permission).

Objections has been raised and another word has to replace "Violation". Quote:

"Violation" assumes malintent. I would expect contributors to react defensively/combatively if they're pointed to a tracker about their contribution with the word "violation" in it. It is more than likely that they are merely confused by the GPL's litany of rules, not intentionally trying to get away with cheating.

I would like to keep the guidance text, but replace the word "Violation" with something less hostile.

That is, the replacement word should not imply, but not completely rule out, malintent.

If possible, the word should be a noun, and it should convey that the problem is not open for discussion, and that some action on part of the contributor is required (all this is probably too much to ask of a single word, but I hope it indicates what I am looking for).

I did an online search for synonyms before asking here, and ended up with the following list: abuse, contravention, encroachment, infraction, infringement, misdemeanor, negligence, offense, transgression – all of which sound too hostile for my use case.