CCS/MSP430FR4133: Power (ULP) Advice does not recognize an unsigned char

Tool/software: Code Composer Studio

I have the following code:

void D5TE_getData(uint8_t *data)
{
	uint8_t i;

	for(i = 13 ; i > 0 ; i--)
	{
		data[13 - i] = rxBuffer[13 - i];
	}
}

and the next advice:

#2553-D (ULP 14.1) Array index (involving "i") of type "int". Recommend using "unsigned int" 

can you tell me why it doesn't recognize the unsigned char since for me it doesn't make sense to put an unsigned int for the

amount of values that are here, I should delete this tip or there is something that I could do