The .dump /ma command produces a dump which generates a lot of warnings when loaded and worked on - how to fix?

Question

Having a crash dump open

0:000> ||
.  0 Full memory user mini dump: c:\temp\dump\0.dmp

I fix some images using .imgscan and re-dump into a new file:

0:000> .dump /ma c:\temp\dump\1.dmp
Creating c:\temp\dump\1.dmp - mini user dump
GenInvokeEnumStackProviders(mscordacwks.dll) failed, 0x8007007e
GenInvokeEnumStackProviders(mscordacwks.dll) failed, 0x8007007e
QuerySystemMemoryInformation failed, 0x80004001
QueryProcessVmCounters failed, 0x80004001
Dump successfully written

I assume the failure messages can be ignored.

Now I close the debugger, reopen and load the new dump. The output is thrashed with gazillion of these messages right away:

Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570

Here is the beginning:

Process Uptime: 0 days 8:26:24.000
................................................................
................................................................
................................................................
................................................................
................................................................
................................................................
................................................................
....
Loading unloaded module list
.........
This dump file has a breakpoint exception stored in it.
The stored exception information can be accessed via .ecxr.
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
For analysis of this file, run !analyze -v
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get current machine context, Win32 error 0n1392
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get program counter
No flat address for current instruction
 ??              ???

Loading Dump File [C:\Temp\dump\1.DMP]
User Mini Dump File with Full Memory: Only application data is available

Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get program counter
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570

Loading Dump File [C:\Temp\dump\1.DMP]
User Mini Dump File with Full Memory: Only application data is available

Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get program counter
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get current machine context, Win32 error 0n1392
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get current machine context, Win32 error 0n1392
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570

Here is how running a command looks like:

||2:0:000> .load c:\utils\sosex\64\sosex.dll
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get current machine context, Win32 error 0n1392

And another command:

|2:0:000> .time
Debug session time: Wed Feb 23 14:29:27.000 2022 (UTC - 5:00)
System Uptime: 0 days 22:15:39.839
Process Uptime: 0 days 8:26:24.000
  Kernel time: 0 days 3:08:40.000
  User time: 1 days 2:53:06.000
Failed validating the extended context size for the thread 1204: 
GetContextState failed, 0x80070570
Unable to get current machine context, Win32 error 0n1392

So even the most innocent command results in these messages.

Why does it happen? How it can be fixed?