Okay, I bit.
I posted a question in that Bachmann forum asking if the fellow was running the engine at or near full throttle.
This is likely, since DCC-equipped engines require high throttle settings just to get over the decoder drop and get the engine to move at all.
While it is true that the peak voltages from the 1370 are technically within the tolerance range specified for decoders, this is all about how much you are willing to live "on the edge". When I build circuits with electrical components, I always choose components that have a healthy margin of error (for example, use a 50v capacitor even if the top voltage you ever expect it to see is 25).
If I recall the DCC spec limit was 27, right? Is it technically okay to hit a decoder with 25 volt peaks? Yes. But is it a good idea? No. And will there be a certain number of new failures brought about just because some of the components aren't quite up to snuff? You betcha.
Let's see what that guy says. If he was running it full-out, that would be another useful data point.