Re: PIC does not wake up everytime
Most likely because if you have an interrupt on change, and then at the same time, or while you are dealing with checking the IOC flags, you have a UART1 receive interrupt, and that then overwrites the variable reveil_t = PC_COMM. Now you have missed whatever IOC event you had flagged as being detected: CONFIG, SENSOR1, SENSOR2 or BATTERY.
Also, where are you checking reveil_t? In your "main" function? What does that code look like?
How quickly can you check reveil_t? What happens if you get another interrupt, and the ISR then updates reveil_t, before you get around to checking the first one?
However we are only guessing, because you have not posted you complete code. If you have a problem with some code and need to ask for help you are not qualified to decide which code you should/should not post for others to be able to help you.