Java Exception when trying to review CR

So we identified the bug: it's a regression directly related with using Change Request with a recent version of XWiki such as 16.10.5, the bug doesn't reproduce on older versions such as 16.10.2. Nonetheless it worked by "accident" in the past so I need to also provide a patch. However, even after it's fixed the error you're seeing in the created Change Request won't disappear: it will just fix the problem for future change requests. If you need to fix existing CR, there's some manual operations to do but it's a bit tedious, let me know if you need it.