Same problem here. iMac Pro 8core 32gb Vega64.
It happens when I am away from the computer for some time. When I come back, it restarted with this message in the logfile.
Interestingly the timestamp is one hour BEFORE it the last Time Machine backup (maybe only because crash reporter uses a different timezone.) I will disconnect my USB-C LaCie Harddrive and see if it still happens. I have no Thunderbolt Devices. Filevault and Powernap is on.
{"caused_by":"macos","macos_system_state":"running","bug_type":"210","os_version":"Bridge OS 3.2 (16P2542)","timestamp":"2018-12-18 08:01:52.55 +0000","incident_id":"2BAEDD31-E93F-4378-8A1C-27E599B2B528"}
{
"build" : "Bridge OS 3.2 (16P2542)",
"product" : "iBridge2,1",
"kernel" : "Darwin Kernel Version 18.2.0: Mon Nov 12 20:24:14 PST 2018; root:xnu-4903.231.4~3\/RELEASE_ARM64_T8010",
"incident" : "2BAEDD31-E93F-4378-8A1C-27E599B2B528",
"crashReporterKey" : "c0dec0dec0dec0dec0dec0dec0dec0dec0de0001",
"date" : "2018-12-18 08:01:52.51 +0000",
"panicString" : "panic(cpu 1 caller 0xfffffff025e1ab14): x86 CPU CATERR detected\nDebugger message: panic\nMemory ID: 0x6\nOS version: 16P2542\nKernel version: Darwin Kernel Version 18.2.0: Mon Nov 12 20:24:14 PST 2018; root:xnu-4903.231.4~3\/RELEASE_ARM64_T8010\nKernelCache UUID: CFF13C89BB4B5456C40AFD66512D8AD8\nKernel UUID: 4BC02A8F-ECD4-37DE-8656-F4FCB742B8C4\niBoot version: iBoot-4513.230.5\nsecure boot?: YES\nx86 EFI Boot State: 0x16\nx86 System State: 0x0\nx86 Power State: 0x0\nx86 Shutdown Cause: 0xec\nx86 Previous Power Transitions: 0x70707060400\nPCIeUp link state: 0x89271611\nPaniclog version: 11\nKernel slide: 0x000000001f600000\nKernel text base: 0xfffffff026604000\nEpoch Time: sec usec\n Boot : 0x5c18a755 0x0003c761\n Sleep : 0x00000000 0x00000000\n Wake : 0x00000000 0x00000000\n Calendar: 0x5c18a95d 0x0009200f\n\nPanicked task 0xffffffe000195680: 2627 pages, 171 threads: pid 0: kernel_task\nPanicked thread: 0xffffffe0004b0f90, backtrace: 0xffffffe0167ab520, tid: 357\n\t\t lr: 0xfffffff026800a08 fp: 0xffffffe0167ab660\n\t\t lr: 0xfffffff0266dd610 fp: 0xffffffe0167ab670\n\t\t lr: 0xfffffff026711ce4 fp: 0xffffffe0167ab9e0\n\t\t lr: 0xfffffff02671205c fp: 0xffffffe0167aba20\n\t\t lr: 0xfffffff026713c94 fp: 0xffffffe0167aba40\n\t\t lr: 0xfffffff025e1ab14 fp: 0xffffffe0167abab0\n\t\t lr: 0xfffffff025e1cf9c fp: 0xffffffe0167abb50\n\t\t lr: 0xfffffff025e1a1d0 fp: 0xffffffe0167abbe0\n\t\t lr: 0xfffffff025dd3ab0 fp: 0xffffffe0167abc10\n\t\t lr: 0xfffffff026b9afa4 fp: 0xffffffe0167abc50\n\t\t lr: 0xfffffff026b9a834 fp: 0xffffffe0167abc90\n\t\t lr: 0xfffffff0266e8614 fp: 0x0000000000000000\n\n",
"panicFlags" : "0x102",
"otherString" : "\n** Stackshot Succeeded ** Bytes Traced 88416 **\n",
"macOSPanicFlags" : "0x0",
"macOSPanicString" : "CPU Machine Check Architecture Error Dump (CPU: UNKNOWN, CPUID: 0x8000000900050654)\r\nCore: 0 \r\n IA32_MC4_STATUS=0xBA00000059000402\r\n IA32_MC4_CTL=0x0\r\n IA32_MC4_MISC=0x0\r\n",
"memoryStatus" : {"compressorSize":0,"compressions":0,"decompressions":0,"busyBufferCount":0,"pageSize":16384,"memoryPressure":false,"memoryPages":{"active":5224,"throttled":0,"fileBacked":9500,"wired":4384,"purgeable":47,"inactive":3080,"free":13422,"speculative":3695}},
"processByPid" : {
(and much more infos…)