Fatal Error: EXC_BAD_ACCESS / EXC_I386_GPFLT with map.find()

I have a map std::map < std::string, Setting* > params and elements are inserting and reading with mutex locks. But I am facing with below crash with find() even though it has locks. This is not recreating always. What may be the possible reasons for the crash? Anyone pls help.

My OS is Mac 11.0.2 and C++.

Fatal Error: EXC_BAD_ACCESS / EXC_I386_GPFLT

Thread 23811 Crashed:
0   ddaemon                        0x104b86a27         [inlined] std::__1::basic_string<T>::__is_long (string:1420)
1   ddaemon                        0x104b86a27         [inlined] std::__1::basic_string<T>::size (string:947)
2   ddaemon                        0x104b86a27         [inlined] std::__1::basic_string<T>::compare<T> (string:3696)
3   ddaemon                        0x104b86a27         [inlined] std::__1::basic_string<T>::compare (string:3714)
4   ddaemon                        0x104b86a27         [inlined] std::__1::operator< <T> (string:3939)
5   ddaemon                        0x104b86a27         [inlined] std::__1::less<T>::operator() (__functional_base:54)
6   ddaemon                        0x104b86a27         [inlined] std::__1::__map_value_compare<T>::operator() (map:516)
7   ddaemon                        0x104b86a27         [inlined] std::__1::__tree<T>::__lower_bound<T> (__tree:2637)
8   ddaemon                        0x104b86a27         std::__1::__tree<T>::find<T> (__tree:2566)
9   ddaemon                        0x104b9e620         [inlined] std::__1::map<T>::find (map:1380)```