Was Procmail's "dropped F" bug ever fixed? If so, when?

For well over a decade, SpamAssassin has provided a sample procmailrc file that includes the following workaround for a Procmail bug:

# Work around procmail bug: any output on stderr will cause the "F" in "From"
# to be dropped.  This will re-add it.
:0
* ^^rom[ ]
{
  LOG="*** Dropped F off From_ header! Fixing up. "

  :0 fhw
  | sed -e '1s/^/F/'
}

Recent versions of this file have an added comment:

# NOTE: This is probably NOT needed in recent versions of procmail

The wording of the comment doesn't exactly inspire confidence about the nonexistence of this bug. Can anyone confirm whether or not the "dropped F" bug still exists in the current release of Procmail? If it no longer exists, in which version of Procmail was it fixed? In the interests of simplicity, I'd happily remove these lines from my systems' procmailrc files, but only if I can be sure that it's safe to do so with the versions of Procmail that they're running.