Since upgrading from the manufacturer's firmare to recent Marlin (first 1.1.9, then 2.0.x git HEAD), I've been having significant model-dependent (didn't happen for first few things I tried to print; other prints reproduce it reliably) layer shifting on the Y axis. It's always in the positive Y direction, usually by 1-3 mm at a time.
I first suspected mechanical problems (see: Ender 3 has developed a tendancy to skip Y steps), but reverting the firmware confirmed that it's a firmware problem.
A number of bug tracker entries for Marlin indicate that there are significant ongoing layer shift problems:
But most end up getting closed. Some people say reverting to 1.1.9 from 2.0.x helped; others say 1.1.9 is EOL and to use 2.0.x. Is there a solution? How do I get a working version of Marlin (new enough to have Linear Advance 1.5, which was my motivation for upgrading) on Ender 3?