There are three places (pages 686, 697, 737) in the DESCRIPTION at the top of the MIB DEFINITIONS that have this text:
"Unless otherwise indicated, the references in this MIB module are to IEEE Std 802.1Q.
Copyright (C) IEEE (2014)."
Most places in the document use "Copyright (C) IEEE (2018)."
Note also that the wording seems to be very consistent throughout except on these pages:
973, 989, 1081, 1815, 1888. Do we care?
Just use the Advanced Search feature of Adobe to search for "IEEE (" to find these places.
Pages 955 (P802.1Qaw D5.0), 1005 (no Std), 1015 (no Std), 1051 (no Std), 1067 (includes 2011), 1072 (strange copyright), 1078 (no Std) are inconsistent. Do we care?
Search for "Included in IEEE" to find these places.