Using CHANGE_SLAB_TYPE next to water leads to patchy gold

[Loobinex]

This gold is placed by script:

Notice the gold slabs have columns of dirt as well as columns of gold. It should be all gold. Here is the testmap: changegoldtest.zip

It's done with a fill command, but it could be done slap for slap too:

CHANGE_SLAB_TYPE(42,20,GOLD)
CHANGE_SLAB_TYPE(42,21,GOLD)
CHANGE_SLAB_TYPE(42,22,GOLD)
CHANGE_SLAB_TYPE(42,23,GOLD)
CHANGE_SLAB_TYPE(42,24,GOLD)
CHANGE_SLAB_TYPE(43,20,GOLD)
CHANGE_SLAB_TYPE(43,21,GOLD)
CHANGE_SLAB_TYPE(43,22,GOLD)
CHANGE_SLAB_TYPE(43,23,GOLD)
CHANGE_SLAB_TYPE(43,24,GOLD)
CHANGE_SLAB_TYPE(44,20,GOLD)
CHANGE_SLAB_TYPE(44,21,GOLD)
CHANGE_SLAB_TYPE(44,22,GOLD)
CHANGE_SLAB_TYPE(44,23,GOLD)
CHANGE_SLAB_TYPE(44,24,GOLD)
CHANGE_SLAB_TYPE(45,20,GOLD)
CHANGE_SLAB_TYPE(45,21,GOLD)
CHANGE_SLAB_TYPE(45,22,GOLD)
CHANGE_SLAB_TYPE(45,23,GOLD)
CHANGE_SLAB_TYPE(45,24,GOLD)
CHANGE_SLAB_TYPE(46,20,GOLD)
CHANGE_SLAB_TYPE(46,21,GOLD)
CHANGE_SLAB_TYPE(46,22,GOLD)
CHANGE_SLAB_TYPE(46,23,GOLD)
CHANGE_SLAB_TYPE(46,24,GOLD)

[AdamPlenty]

Patchy gold happens with the place terrain cheat too.