My I2C Can't Read Bytes When The MSB Is 1

I have a SAMD21 which us a slave to a SAMD20. Whenever the D20 reads a byte from the D21 in which the byte starts with a 1, its clock is released and then so is the data line. I have no idea why it’s doing this and countless debugging methods have proven to be fruitless. I thiught I would come on here to see if anyone might have an idea as to why this is happening. Thanks!

Need more info. There could be million reason for this problem. Could you please share your code, at least the relevant parts? Are you using any framework in your code? Is it a development board or a custom board?