The alerts from the GPWS below 1000' signify an unstable approach, you go around, the end.
What they will investigate is the why they did not go around, but it's largely irrelevant.
It's always relevant but the NTSB's recommendations sometimes fall on deaf ears in a way that endangers future safety.
Hopefully not without some very thorough additional training and certification.
Is this an issue with the re-training of rotor to fixed wing pilots?
The thing I've heard from the fine folks on the pilot forums is that for most airlines (granted, passenger airlines, not necessarily cargo), the reverse is usually true. An unstable approach generates a number of these warnings and the plane tattles on the pilot in real time, there will be repercussions for not going around.