* UPDATE *
Replaced the timer instance in the RTC module by calls to Task_sleep(). Still crashing.
In the timer instantiation code "Timer_create()", replaced "Timer_ANY" by 4. Not crashing anymore.
Tested all possible values for ID parameter. Application crashes if ID < 4, it works if ID is 4 or 5. After this point I remembered that for the RTC timer I was using 4 as ID, this is why it was working all the time.
Is there a reason for the I2C module not work when timer 0, 1, 2 or 3 are enabled?