As discussed under 2 Nephi 29:14, the critical text will restore the plural possessions here in Alma 50:12 (thus “upon the lands of their possessions”). 𝓞 is not extant here but probably read “upon the lands of their possessions”, just as in 𝓟. The 1830 typesetter accidentally replaced the plural possessions with the singular possession. The RLDS text restored the original plural in 1908, but the LDS text has maintained the secondary possession. Note the use of the plural possessions earlier in this passage (“from off the lands of their possessions”); in that case, the plural possessions is extant in 𝓞.