If any wires were to become pinched, and if these wires only had a very thin layer of Teflon insulation, rather than much tougher PVC based coverings....
Been lurking quietly and following various aspects of this thread. The above may be an important clue, especially with respect to the ELT. One of the interesting
features of teflon insulation (FEP and PTFE) is that in a stressed situation it will slowly do something referred to as 'cold flow'. I first witnessed this about 40 years ago, involving some teflon insulated wire-wrap circuits, on a Univac backplane, where the wires had been pulled too tight against a 90-degree turn, and the teflon insulation eventually cold-flowed to the extent that it made electrical contact with the wire-wrap post that the turn was against. That the battery wire in the ELT appear to have been 'pinched' (based on various sources) and the likelihood that it could be teflon insulated as well, this could be a delayed cold-flow event. The unit was assembled, tested, everything looked good, and then (over time) the pinched insulation flowed back, and a short developed. One possible theory on how this occurred. If so, it is very lucky that the incident happened on an airframe sitting on the stand, with no pax on board.
NASA makes mention of 'cold flow' on this page (right most column, first entry) ...
NASA Parts Selection List (NPSL) - Wire Insulation Selection Guidelines