The intermittent wipers on my Model X (2017) also stopped working some time since the last couple of months, and is still nonfunctional in the update pushed last night. This appears to be a defect in FSD beta. Auto wipers toggle makes no difference.
As nonfunctional wipers are a safety hazard, and this has already obviously been broken for more than a month (which is about three weeks longer than reasonable for such a serious bug), I filed a NHTSA complaint.
Tesla needs to hire an actual QA testing team. A bug this serious should never have made it into a build that was distributed widely, much less still remain unfixed in subsequent builds. Anything that diminishes people's ability to drive the car in non-AP mode should be considered a showstopper, and they should absolutely stop everything until they fix it. This is NOT okay.