This is one of several similar edits done by IAB yesterday (1 September 2019).
They all seem to be related to the presence of "ref group" in the references.
It looks like the bot "merges" several references with the same content with "ref group=1" just like they were "ref name=1".
Please investigate this and configure the bot to avoid these type of edits.
Here are a few more articles where I have just reverted the IAB edits: