Yeah, I've seen that it's supposed to check for recent tag and if not found, takes first commit. I see no good alternative of filtering out this log. Development did took 3 years since https://github.com/Elgg/Elgg/commit/6c26a47e6f05c6939a63b5de95bff52eaa2f49d3 and filtering out commits existing on 1.8 branch doesn't seem to work correctly.