Pre 1.08 (& 1.09) it was not uncommon to get 0 gold or 4 gold on a defence loss (assuming that an invader had a much stronger team, good board control or some lucky drops).
For a defence win, the gold is always >100, so I assume for a Defence Win it is 100 gold + what is won in battle.
Now the lowest I’ve seen on a single defence loss in many months is 24 gold. Is there now a minimum gold amount for a defence loss?