Well, T'ien Ch'i has no spheres, so it's obviously to my advantage to drop them to allow BF spells to work.
We could do a trial run. Don't use them for a turn and see if the enchantments work?
Either that or someone can try to duplicate the problem in an SP test game. See if you can figure out what the actual limits are. I'm not going to have time for that in the next couple of days though.
I'm not sure I've actually seen the issue. I definitely had BF enchantments the turn before last. Life after Death didn't seem to work, but it showed up as normal in the debug log. Relief did work.
None were used this past turn.