@BudWalker - sorry to hear about your accident. Nobody is going to accuse you of pilot error if you're willing to upload the logs for a review. Someone on this forum should be able to determine exactly what caused your issue. You may want to wait until after they analyze your logs before you make your decision as to whether or not to send it in. DJI uses the logs to determine what happened - so they're going to see the same thing that we see on the forum. If the logs don't point to obvious pilot error, then I think it's definitely worth sending it in for DJI's analysis. Even if you're repair is not fully covered under warranty - it may still be affordable enough to have it done.
There's a big difference between your story and Roman's. On your very first post, you offered to provide logs. Romans109 ignored requests for logs for almost 100 posts just screaming "believe me believe me" before he even acknowledged the people offering to look at them and then mysteriously was unable to provide them. I think your experience here in the forum will be completely different than his was - and I do hope that the logs show a clear malfunction so you can get your unit repaired under warranty.
I've just started playing with the "follow" function using the AutoPilot software. My first 2 flights have gone perfectly - but if there is a possibility of malfunction, I'd like to know what causes it to make sure I'm not vulnerable.
One thing you should be aware of is that the DJI Go follow mode doesn't adjust the altitude as you travel up and down hills. Everything is relative to where you powered on the drone. Here's one (unlikely) scenario that could cause an accident similar to the one you described: You power up the drone and set it to follow you at 60ft and then get in the car and test it briefly. It's working - so you land it, get in the car without powering off the unit and drive to a park a few minutes away but actually at a new elevation (with respect to sea level). Your new location is actually 100ft higher than where you first powered on the drone. You think your altitude is 0 but because you didn't power cycle the drone - ground level for you now is 100ft in the mind of the drone and the 60ft "follow" height is now -40ft from your new ground level!!! If you took off from this new location and engaged follow mode - the drone would try to fly to 60ft above your original location which is 40ft BELOW your current location (which would be underground).
I'm not suggesting that this is what you did - bit with all the recent talk of "follow mode" accidents, I thought this was a good place to explain why it's important to be aware of changes in altitude. Especially when driving, sometimes the changes happen so gradually that they are not obvious. Anyhow - the scenario I laid out above is one way to explain how/why a drone could decide to dive bomb the ground at a 45 degree angle right after follow mode is engaged.
One of the great features of the Autopilot software is that it can be told to be aware of elevation changes and to keep the drone 60ft above the targets CURRENT location - not just his STARTING location. So far, I think purchasing Autopilot is the best 25 bucks I've ever spent! If you haven't looked at it - I recommend you check out their tutorials on YouTube and see if it might be a good investment for the type of flying you do. Saying that it is a "feature rich" platform would be an understatement.
In any case - for anyone else experimenting with follow mode - I suggest you start with the drone WELL above the height you want to follow at - and as you first engage the follow function, have your finger on the PAF switch and at the first sign that something is not right - flip it into P mode immediately. That should cause it to stop and hover.