Sadly, I have the same issue, with a Kensington SD5600T dock, with two 4K external monitors. Usually, I can get the laptop to boot and both monitors to power on and display an image (not always, though). All it takes to get a crash is to disconnect the Thunderbolt cable and connect it again. I have no issues if I connect the monitors directly to the laptop. {"caused_by":"macos","macos_version":"Mac OS X 11.4 (20F71)","os_version":"Bridge OS 5.4 (18P4663)","macos_system_state":"running","incident_id":"A55327BC-9C3D-4287-A718-9E95DC783DB8","timestamp":"2021-07-01 08:39:39.00 +0000","bug_type":"210"} { ... "build" : "Bridge OS 5.4 (18P4663)", "crashReporterKey" : "c0dec0dec0dec0dec0dec0dec0dec0dec0de0001", "date" : "2021-07-01 08:39:39.76 +0000", "incident" : "A55327BC-9C3D-4287-A718-9E95DC783DB8", "kernel" : "Darwin Kernel Version 20.5.0: Fri May 7 22:04:14 PDT 2021; root:xnu-7195.121.3~8\/RELEASE_ARM64_T8010", "macOSOtherString" : "\n** In Memory Panic Stackshot Succeeded ** Bytes Traced 400304 (Uncompressed 988640) **\n", "macOSPanicFlags" : "0xc", "macOSPanicString" : "panic(cpu 1 caller 0xffffff801c09f846): [kext.kalloc.2048]: element modified after free (off:1584, val:0x0000210100000000, sz:2048, ptr:0xffffff937950b000, prot:zero)\n 1584: 0x0000210100000000\n 1592: 0x0000000b00000c00\n 1600: 0x000000010000000d\n 1608: 0x0000061f00000000\n 1616: 0x0000028a00000154\n 1624: 0x0000001000000a00\nBacktrace (CPU 1), Frame : ... "panicFlags" : "0x902", "panicString" : "panic(cpu 1 caller 0xfffffff011488190): macOS panic detected\nDebugger message: panic\nMemory ID: 0x6\nOS release type: User\nOS version: 18P4663\nmacOS version: 20F71\nKernel version: Darwin Kernel Version 20.5.0: Fri May 7 22:04:14 PDT 2021; root:xnu-7195.121.3~8\/REL EASE_ARM64_T8010\nKernel UUID: 873F4AC5-B66C-3016-8EAC-39D538EEB5A3\niBoot version: iBoot-6723.120.36\nsecure boot?: YES\nx86 EFI Boot State: 0x16\nx86 System State: 0x0\nx86 Power State: 0x0\nx86 Shutdown Cause: 0xf5\nx86 Previous Power Transitions: 0x70707060400\nPCIeUp link state: 0x892 71614\nPaniclog version: 13\nKernel slide: 0x000000000952c000\n ...