Unfortunately there are not automatic tests which we can use for IPR, because crashes are more likely to occur when scene is handled interactively, and everything depends of the current scene's state.
I mean, using a same scene and configuration, it would crash just because a render thread runs a millisecond before of after, and that is unpredictable.
Said that, we have not received lately problems with IPR, so we assumed with the latest fixes it was working reasonable well.
We'll do some manual tests again, but please note we cannot test all possible combinations of Max, V-Ray and scene components.
A simple minidump sent by you or other customer, may solve a problem that otherwise, we never know that it exists.
Thanks for your understanding.