Strange behaviour - Wrong Variable Values

Hi,

All of a sudden, I've got a very strange bug? with MT5 showing completely wrong variables values in my indicator.

ALL variable values are wrong.

Example:

int test = 1;
printf(test);

Output:
34581140

Output from iRSI is for example:
1.708535919681431e-316

All was working fine until last week Wednesday. I didn't change anything on the indicator since then!

I'm completely lost!

Does anyone have an idea what this could be?
Some wrong setting in MT5?
Bug?

Please help! Thanks!