I know that the Catholic church is not a bible only church. The point is that rules have evolved...and they have also changed. I wish I could recall what the church just apologized for that happened like 500 years ago. It took them a long time to acknowledge it. Point is, there have been errors.
I think it was one of those politically convenient ecumenical things that happens from time to time. But if I recall correctly, it did not involve Church doctrine per se but merely the imposition of a penalty which some believe to have been unjust.