I have repeated the problem on a MSP430F5528 with CCS 5.4.0.00091, MSP430.dll v3.3.0.6 and MSP-FET430UIF v1.4a.
What seems to be happening is the address of the currently executing function is correctly handled as 20 bits, but the address of the calling function is truncated to 16 bits and thus the callstack is truncated. e.g. in the following example func_a should be shown as being called from main at main.c:34 0x010838:
Howewver, the return address is truncated to 0x000838 which means the return address can't be resolved and the call stack stops.
I guess the error is in how CCS traces the call stack in memory. To get the call stack correct does CCS need to enhanced to detect if the currently executing function was called with either CALL (a 16 bit return address on the stack) or CALLA (a 20 bit return address on the stack)?