beta 528
I just tried to load a few esp1 enemy csets to cset 9 and it's not working at all when you go to the tilepage and change to cset 9 to view the enemy.
IF you put your editor on cset 9 and then go in and load, say cset 0 from esp1, then you see the combos on the right change to that palette, but when you go into the tile pages it is not loaded properly.
I went back and looked, it works in beta 254, the next oldest beta I have on my system is 473 and it's busted in it, so it happened somewhere in between those.