uxTaskGetStackHighWaterMark returns UBaseTypet which is defined as an unsigned char on 8-bit architectures. This function's return type needs to be at least a uint16t in order to work correctly with stack sizes larger than 256 bytes. Some parts like XMegas have enough SRAM that this is a problem.
UBaseTypet uxTaskGetStackHighWaterMark( TaskHandlet xTask )
Thank you for your feedback. In your case you can safely edit the code
to use a uint16_t instead. Remember to make similar edits inside the
function itself, not just the return value.