Please keep in mind that all work on void is done by volunteers, some of which are maintaining hundrets and even thousands of packages. In that regard it is impossible to extensively test every new version of every package, especially if the maintainers are not actively using them themselfs. When you encounter a problem like this please report it here (like you did) or in the GitHub issue tracker.

As for downgrading, the process is a little fiddly. I usually create a temporary repository, add the older package from the xbps package cache to it and that use that repository to force-downgrade the currenty installed package. Something like this:

mkdir /tmp/repo
cp /var/cache/xbps/<packagefilename>.xbps* /tmp/repo/
cd /tmp/repo
xbps-rindex -a <packagefilename>.xbps
xbps-install --repository=/tmp/repo -f <package>