I have just rescheduled
#2167 (pseudo-random de-hoists) for Leo 6.5. No simple and safe fix seems likely.
The ekr-hoist-bug branch now contains an extensive trace in the one place where an unexpected (an automatic) de-hoist seems likely. I'll keep the branch up-to-date with devel, so you won't miss anything.
If this issue affects you please run Leo from the ekr-hoist-bug branch. Traces go to the console, so be sure to run Leo from a console.
If you do see the trace please report it here. And be sure to report if a de-hoist happens without a trace. Thanks.
Edward