powered v. unpowered frogs - Model Railroader Magazine

As to track shorts causing loco decoders to burn out, you can theorize all day long as to why it shouldn't happen, the point is it does happen (it's rare, but I've had a couple of these in 12+ years of using DCC). And if a short doesn't occasionally burn out the decoder, then its even more common for a short to "scramble" the decoder's programming (I've had this happen well over a dozen times with a short).

I believe what happens is a short is a "tramatic event" on your layout, and somehow the sensitive electronics of a decoder, when the current flow through the decoder is involved in a short, millisecond tramatic and unexpected changes in current flow that the circuit was never designed for will scramble the "state" or worse fuse some of those microscopic silicon gates in the decoder.

That's why I prefer dead frog turnouts and why I use 1156 auto tail light bulbs ($1 each) wired in series with the track power bus to "manage" any track shorts and turn them into a non-event. After going to all dead frog turnouts and 1156 bulb short management on my DCC layout, short-induced burned out decoders or short-induced scrambled decoder programming has become a thing of the past.

For more details on how the 1156 tail light bulb short management works, you can watch this video clip demonstration.