OldBackupDirectory timestamp init bug causes NPEs from SnapShooter?

On IRC, a 6.2.0 user reported getting an NPE from SnapShooter.deleteOldBackups L244, with the only other frame of the stacktrace being lambda$createSnapAsync$1 L196 (it was a screenshot, not text easily cut/paste here)

The problematic L244 is...

  if (obd.getTimestamp().isPresent()) {

..and i believe the root of the issue is that while getTimestamp() is declared to return an Optional<Date>, there is no guarantee that the Optional instance is itself non-null...

   private Optional<Date> timestamp;

  public OldBackupDirectory(URI basePath, String dirName) {
    this.dirName = Preconditions.checkNotNull(dirName);
    this.basePath = Preconditions.checkNotNull(basePath);
    Matcher m = dirNamePattern.matcher(dirName);
    if (m.find()) {
      try {
        this.timestamp = Optional.of(new SimpleDateFormat(SnapShooter.DATE_FMT, Locale.ROOT).parse(m.group(1)));
      } catch (ParseException e) {
        this.timestamp = Optional.empty();
      }
    }
  }

Allthough i'm not 100% certain, I believe the way the user was triggering this bug was by configuring classic replication configured with something like <str name="replicateAfter">commit</str> – so that usage may be neccessary to trigger the exception?

Alternatively: perhaps this exception gets logged the first time anyone tries to use any code that involves SnapShooter – and after that a timestamp file is created and teh problem neer manifests itself again?