The phrase "serious rift" means a big and significant disagreement or conflict between people or groups that can potentially cause lasting damage or division. Full definition
Following which, as in the Mainline, serious rifts opened among Catholics on social and economic issues. (firstthings.com)
«The fact that there is a serious rift after 6 years with the organization, the fact that there is a lack of trust on Kawhi's part...» I think you need to redefine the word «fact». (sbnation.com)
... a serious rift in American culture and the body politic clearly exists. (unitywoods.com)