System: MacBook Pro (16-inch, 2019) OS Version: Big Sur 11.4 (20F71) Graphics: AMD Radeon Pro 5500M 4 GB, Intel UHD Graphics 630 1536 MB I had encountered the same problem. Unplug and Plug USB-C cable to MacBook and Kernal panic 'element modified after free'. I'm following this thread from quite sometime now just to find any fix/workaround. Home setup: dual monitors - DELL P2421DC directly connecting via USB-C cable (cable is from Dell, out of box with new monitors). Office setup: dual monitors - DELL U3821DW directly connecting via USB3.1 Type C cable (80C 30V - is printed on wire) -> https://www.bizlinktech.com/products/detail/1240/USB+3.1+Gen+2+Type-C+Active+Cable And surprisingly when I connected my MBP to external monitors in office last week, no crashes. I tested my home setup with Bizlink USB3.1 Type C cable and didn't encountered any crashes so far. I'm not sure how these cables differ. I couldn't find anything written on Dell USB-C cable to figure out.