It appears to be totally broken in 1.19. I can't appear to mod any core xml in the data directory. Even recompiling the data.zip does nothing.
Here is another good one.
Decided to change the cost of teleportation. I copied the Strat mobility to the mods folder and changed the cost. Fired up a game and was greeted with two mana cost lines in the spell, but the spell worked and cost me the combined cost. Next I gutted my mod file just to leave the mana cost element in there. Still got duel cost and now the spell does not work. I click on a new square, I get an animation, but my Sov is still stuck where he was. Mana burned. I decided to go postal on the situation. I killed my mod file. I change the cost in the data xml file. I recompiled the data.zip. Started a new game and bam! Spell shows up with its original cost. The 64 peso question: Where did that data come from?
I'm baffled. Maybe one of the Mod Gods will know what is up.