One of the sites that I maintain saw a large spike in bounce rate beginning March 1, 2017. Previously, the bounce rate held steady around 50%, but rose to 80% in March and has stayed there. We have not made any updates to this site that would've caused an adverse response in user experience. Additionally - there does not seem to be any real change in traffic, acquisition sources or site speed/performance that I can see that could be associated with this change. Finally, there does not seem to be anything inaccurate about how the tracking code is placed.
Any ideas on why the bounce rate would've spiked like this and remains elevated?