I2C issue with STM32H7 MCU

Hello.,.,

 I am using STM32H7 newly released MCU in our project,  In this 3 slave devices are connected thorough I2C interface (Audio codec,EEPROM,RTC devices), All slave devices are accessible and working fine with room temperature , But when we tested the same unit with 70 Celcius temperature The I2C link become unreliable . Can anyone suggest what could be done to resolve this issue I tried by changing I2C clock in both higher and lower values (Currently I2C clock @ 100KHZ) but end up with same status. 

Also during analysis I observed a bug with the Micro controller(STM32H765BIT),  A default 200KHZ is generated from contoller (Through PIN 101, same pin i am using as I2C clock pin ), even I erased the complete the flash still by default clock is coming out (I cross checked by removing VCC from MCU , that time clock is not coming ) , I suspecting This could be the one reason that makes I2C unreliable.  

Can some STM people spare some time to resolve this issue , We stuck on this issue for long time, Any small help would be appreciated lot.

Thank you.,