Possible problem with using xpcall

I’m trying to use calls to xpcall in order to include stack traces in my logging and I’m running into a problem.
If the function passed to xpcall raises an error, the error is suppressed as expected but I lose subsequent annotations. I’ve included an example main function which shows this.
Am I missing something?

Thanks for any insight…

function main()
   
   iguana.version();   --tested in v6.0.5
   trace(_G._VERSION);   --tested in Lua 5.1

   local testinputBad = 'This is not good JSON';
   local testinputGood = 
   [[{
      "Attribute1" : 123456, 
      "Attribute2" : 'A Cortado Breve', 
      "Attribute3" : 
      {
         "FirstName" : 'Ralph',
         "LastName" : 'Cramden', 
         "Wife" : 'Alice Cramden'
      }
   }]];

   --NOTE: both successful and unsuccessful calls to pcall act as expected.
   local Success1, result1 = pcall(json.parse, {data=testinputBad});
   local Success2, result2 = pcall(json.parse, {data=testinputGood});   

   trace(Success1, result1);
   trace(Success2, result2);
   
   --NOTE: when the unsuccessful call to xpcall executes ("local Success3, result3 = ...")
   --subsequent annotation stops (except for the next call to xpcall).
   --If you comment line 30 (the bad call) the subsequent annotations are restored.

   local Success3, result3 = xpcall(function() return json.parse{data=testinputBad}; end, ErrHandler);
   local Success4, result4 = xpcall(function() return json.parse{data=testinputGood}; end, ErrHandler);
   
   trace(Success3, result3);
   trace(Success4, result4);
end

function ErrHandler(errmsg)
   trace(errmsg);   
   return errmsg .. '\n' .. debug.traceback();   
end