There have been a lot of bug fixes since Audacity 2.1.2, and there are several more bug fixes in the soon to be released 2.2.2 version.
I’d suggest that you try using Audacity 2.2.2 beta which is available here: https://www.fosshub.com/Audacity-devel.html/
If that fixes the problem, update to the release version of 2.2.2 as soon as it is available (the release will be announced on this forum, and on the main Audacity website, and on our social media (see links at top of page),