Read Access Violation on copy of existing element to new element

[streetjimmothy]

Version of Boost

1_84

Steps necessary to reproduce the problem

Expected Behaviour: assigning an existing property on a JSON to a key that does not exist should work the same as when the assignment is made to an existing key, or when any other value is assigned to a key that does not exist.
Actual Behaviour: read access violation
Case 1:
object["existing_key"] = object["old_key"]; //works
Case 2:
object["new_key"] = "new_value"; //works
Case 3:
object["new_key"] = object["old_key"]; //read access violation

Call stack & Error details:

Exception thrown: read access violation.
this was 0xFFFFFFFFFFFFFFFF.
boost_json-vc143-mt-gd-x64-1_84.dll!boost::container::pmr::memory_resource::is_equal(const boost::container::pmr::memory_resource & other) Line 59
boost_json-vc143-mt-gd-x64-1_84.dll!boost::container::pmr::operator==(const boost::container::pmr::memory_resource & a, const boost::container::pmr::memory_resource & b) Line 66
boost_json-vc143-mt-gd-x64-1_84.dll!boost::json::value::swap(boost::json::value & other) Line 390
boost_json-vc143-mt-gd-x64-1_84.dll!boost::json::value::operator=(const boost::json::value & other) Line 268

[streetjimmothy]

As I was writing the above, I discovered that you don't get the error if any new element is assigned prior to the copy.
This works:
object["new_key"] = "new_value";
object["another_new_key"] = object["existing_key"];
This does not:
object["another_new_key"] = object["existing_key"]; //read access violation
object["new_key"] = "new_value";

[grisumbras]

Please provide a minimal complete verifiable example, so that I can attempt to reproduce the error. As is, I tried locally, and the error you are describing doesn't manifest.

[streetjimmothy]

Thanks for the quick response; I'll whip one up in the next few days