Running version Version 2.3.5 (build 2625.189a587c37 dated 2020-11-16) on Ubuntu 18 LTS.
Error:
/home/kasper/cadabra2/libs/nlohmann/nlohmann/json.hpp:20218: const value_type& nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::operator const [with T = const char; ObjectType = std::map; ArrayType = std::vector; StringType = std::__cxx11::basic_string; BooleanType = bool; NumberIntegerType = long int; NumberUnsignedType = long unsigned int; NumberFloatType = double; AllocatorType = std::allocator; JSONSerializer = nlohmann::adl_serializer; BinaryType = std::vector; nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::const_reference = const nlohmann::basic_json<>&; nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::value_type = nlohmann::basic_json<>]: Assertion `m_value.object->find(key) != m_value.object->end()' failed.
Aborted