In one of my previous posts I have mentioned some troubles concerning R70 to R75 upgrade, blaming (together with CP support engineers) IPS database.
In fact the issue was related to something completely different. The customer has had a time object, like one on the picture.
As you can see, the second, not the first "Restrict" checkbox is enabled. If the first checkbox is not marked, this object causes policy compilation failure on R75. Mind it was working just fine on R70.