By default the Call Stack Mode is set to Only user functions. In this case, try changing the Call Stack Mode to User / system functions or User functions +1 then analyze the call sequence to see if you can obtain additional detail. Each row in the stack represents a function that called the function in the row above it. Functions in grey font color represent system functions. When the call stack mode on the filter toolbar is set to Only user functions, the system functions are shown at the bottom of the stack. When set to User/system functions, the system functions are shown in the correct location, according to the call sequence.
If the behavior persists, can you provide an example that can be compiled to work with?