Was this DPC made of PTFE? The whole house has slid, including ground bearing slabs?Because that is exacly what has happened - we had a very dry Spring and Summer, large trees adjacent have caused shrinkage and the footing has dropped slightly. The house has therefore tipped forward slightly and the masonry slid over the dpc where the bond is weakest.
The laws of physics would mean the foundations must have dropped to create something like a 20° angle