This bug was already reported in https://bugzilla.samba.org/show_bug.cgi?id=8269 and was fixed for 3.5 it seems. In 4.2.14 it's back again.. Also see https://bugzilla.samba.org/show_bug.cgi?id=8269#c4 in the old bug report.
Fixed somewhere along the way in this series of commits: 9c12232f1ae36e00d04114ad73edd8ba3c2c6a5c d2fe0bf776dc17b66dcd3ff907c1ff5a43eceeb6 5d1a8d2a31390762c471229c2b115147ad0857fe Now we only log this at levels greater than 2.