<URL: http://bugs.freeciv.org/Ticket/Display.html?id=18888 >
There are actually quite a few reports on this topic (see PR#14969),
and several proposed solutions.
The most comprehensive requires new data structures to support the
commercial civ variants (and import of those scenarios). This
is/was a long-term goal of the project.
The simplest (and a patch that exists) merely makes the special
inactive on the wrong terrain, so that terraform back to the
original will give the original special. I've already promised to
adapt that patch to the current source.
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