[[elink3 bug mysteriously doesn't show up]]

Do you compile with either options DEBUG or options DIAGNOSTIC?

How about with options MCLSHIFT=12?   I always see the bug  with that.

This bug may very likely involve register misallocation (possibly of
bp), which in turn is likely to trash the stack. The precise effect of
that depends what stackframes are active (which, of course, depends
partly on what other devices are active on your system.)

I can send assembly output for elink3.c both with and without the bug,
if that'd help...