hello, I have a problem with connection I2C with 2 PICs

I have a PIC16F1933 (Slave) connected to PIC18F2685 (Master) by I2C connection.

My problem is:

SLAVE PIC send to Master value b00001010, master PIC receives this value, all correct, immediately after SLAVE PIC send to Master PIC the value b00001010 and PIC master receives b00000101 (INCORRECT VALUE), immediately after SLAVE PIC send to Master the value b00001010 and PIC master receives b00001010 (CORRECT VALUE), there is a shift and lose the first bit. I have in Master PIC connected a LCD, I see in DEC format: 10,5,10,5,10,5,10.... not 10 constant value because SLAVE PIC send the same constant value b00001010. I have 4k7 resistor in SDA and SCL lines and PIC master working correctly with others SLAVE devices in Read/Write (DS1307) in the program code, my problem is communication with this 2 PICs.

suggestions, help?