ICM42688 acceleration values completely wrong during selft test

Hello, I'm working on a device with the ICM-42688 MEMS sensor and recently I've been implementing the self test feature. At first glance it worked very well, the acceleration values go to 2 m/s². But on repeat tests, the acceleration values don't go to 2 m/s², they go to a range between 20m/s² and 48 m/s². That in turn makes the self test fail.
I tested it on 3 different sensors and they work normally on pretty much all of my tests, only having this problem on the self test. I do think it might be some kind of issue with my code and configuration.

It is from my work, so some I can't share all of the code. What I can share is the following:

`
uint8_t ret = 0, count_out = 0;
while ((ret = ICM_begin() != 0) && (count_out++ < 1))
DWT_Delay_us(1000);
setODRandFSR(ODR_2KHZ, FSR_0);
startAccelMeasure(LN_MODE);

ICMAccelTriplet_t accel_data = {.x = 0, .y = 0, .z = 0};

memset(base_data.acc[EIXO_X], 0xff, sizeof(base_data.acc[EIXO_X]));
memset(base_data.acc[EIXO_Y], 0xff, sizeof(base_data.acc[EIXO_Y]));
memset(base_data.acc[EIXO_Z], 0xff, sizeof(base_data.acc[EIXO_Z]));
base_data.array_counter = 0;

uint32_t start = DWT_GetMicros();
uint32_t last_micros = start;
uint32_t current_micros = start;
while (base_data.array_counter < 50)
{
if (current_micros - last_micros >= 1000) // para executar uma leitura à cada 1ms mais ou menos
{
last_micros = current_micros;
if (ICM_get_accel_data(&accel_data) != HAL_OK)
return EIO;
base_data.acc[EIXO_X][base_data.array_counter] = accel_data.x;
base_data.acc[EIXO_Y][base_data.array_counter] = accel_data.y;
base_data.acc[EIXO_Z][base_data.array_counter] = accel_data.z;
base_data.array_counter++;
}
current_micros = DWT_GetMicros();
}
float low_level_avg[3] = {0.0, 0.0, 0.0};
for (uint8_t i = 0; i < 50; i++)
{
low_level_avg[EIXO_X] += base_data.acc[EIXO_X][i] / 50;
low_level_avg[EIXO_Y] += base_data.acc[EIXO_Y][i] / 50;
low_level_avg[EIXO_Z] += base_data.acc[EIXO_Z][i] / 50;
}

if (writeReg(ICM42688_SELF_TEST_CONFIG,
ICM42688_SELF_TEST_ACCEL_ST_POWER | ICM42688_SELF_TEST_EN_AZ_ST |
ICM42688_SELF_TEST_EN_AY_ST | ICM42688_SELF_TEST_EN_AX_ST) != HAL_OK)
break;

while (base_data.array_counter < 100)
{
if (current_micros - last_micros >= 1000) // para executar uma leitura à cada 1ms mais ou menos
{
last_micros = current_micros;
if (ICM_get_accel_data(&accel_data) != HAL_OK)
return EIO;
base_data.acc[EIXO_X][base_data.array_counter] = accel_data.x;
base_data.acc[EIXO_Y][base_data.array_counter] = accel_data.y;
base_data.acc[EIXO_Z][base_data.array_counter] = accel_data.z;
base_data.array_counter++;
}
current_micros = DWT_GetMicros();
}
float high_level_avg[3] = {0.0, 0.0, 0.0};
for (uint8_t i = 50; i < 100; i++)
{
high_level_avg[EIXO_X] += base_data.acc[EIXO_X][i] / 50;
high_level_avg[EIXO_Y] += base_data.acc[EIXO_Y][i] / 50;
high_level_avg[EIXO_Z] += base_data.acc[EIXO_Z][i] / 50;
}

float accelDiff[3] = {
fabs(high_level_avg[EIXO_X] - low_level_avg[EIXO_X]) * 1000.0f,
fabs(high_level_avg[EIXO_Y] - low_level_avg[EIXO_Y]) * 1000.0f,
fabs(high_level_avg[EIXO_Z] - low_level_avg[EIXO_Z]) * 1000.0f,
};

writeReg(ICM42688_REG_BANK_SEL, 2); // select register bank 2

uint8_t self_test_data[3];
readReg(ICM42688_XA_ST_DATA, &self_test_data[EIXO_X], 1); // accel self-test output generated during manufacturing tests
readReg(ICM42688_YA_ST_DATA, &self_test_data[EIXO_Y], 1); // accel self-test output generated during manufacturing tests
readReg(ICM42688_ZA_ST_DATA, &self_test_data[EIXO_Z], 1); // accel self-test output generated during manufacturing tests

float ratio[3];
ratio[EIXO_X] = accelDiff[EIXO_X] / (1310.0f * powf(1.01f, self_test_data[EIXO_X] - 1) + 0.5f);
ratio[EIXO_Y] = accelDiff[EIXO_Y] / (1310.0f * powf(1.01f, self_test_data[EIXO_Y] - 1) + 0.5f);
ratio[EIXO_Z] = accelDiff[EIXO_Z] / (1310.0f * powf(1.01f, self_test_data[EIXO_Z] - 1) + 0.5f);

ret = HAL_OK;
if (ratio[EIXO_X] < 0.5f || ratio[EIXO_X] > 1.5f)
ret = EIO;
if (ratio[EIXO_Y] < 0.5f || ratio[EIXO_Y] > 1.5f)
ret = EIO;
if (ratio[EIXO_Z] < 0.5f || ratio[EIXO_Z] > 1.5f)
ret = EIO;
`

So to elucidate on some of the functions that might not be that obvious:
"readReg" and "writeReg" both serve to read and write to the registers, as the names imply.
"ICM_get_accel_data" reads the current acceleration values for X, Y and Z.
"ICM_Begin" simply checks if the current sensor truly is an ICM42688 and resets the sensor.

Thank you for any help you might be able to give.