As explained under 3 Nephi 4:18, the 1837 compositor tended to accidentally set to in place of the archaic unto. Here in 3 Nephi 18:11, the 1908 RLDS edition restored the original unto to the RLDS text (apparently by reference to the printer’s manuscript). On the other hand, the LDS text has retained the secondary to in this passage.
The Book of Mormon text definitely prefers the preposition unto in the verb phrase “to do something (un)to someone”. There are 23 other instances with unto but only three with to (and the last two occur in a single quote from the Sermon on the Mount):
Thus the use of unto here in 3 Nephi 18:11 is wholly appropriate, and the critical text will restore it.
Summary: Restore in 3 Nephi 18:11 the original unto, the reading in both 𝓟 and the 1830 edition; the 1837 compositor tended to accidentally replace unto with to.