Debugger shows wrong memory values

I am debugging a STM32H with platformio and ST LINK V2. The SP register is initialized to end of memory at 0x24080000 and at the breakpoint it’s 8 bytes deep: SP=0x2407fff8.

                0x24080000                _estack = (ORIGIN (RAM_D1) + LENGTH (RAM_D1))

If I display the memory in the debugger with start=0x2407fff8, size=0x8, I get a proper display of the memory:


However, if I display the memory with start=0x2407fff8, size=0x10 (8 bytes beyond the end of the memory), it shows all 16 bytes as zero:


I would expect it to display properly the eight bytes that are in memory (preferred), or at minimum, give an error message and display nothing. The current behavior is confusing.