In this paper, we explore an abstraction of uniform integrability in vector lattices and demonstrate its application by providing a positive solution to an open question posed by Kuo, Rodda, and Watson [Proc. Amer. Math. Soc. 147 (2019), pp. 1597–1603]. Specifically, we show that for every p ∈ ( 1 , ∞ ) p\in (1,\infty ) and with T T as a conditionally expectation operator, spaces L p ( T ) L^{p}\left ( T\right ) are sequentially complete. Furthermore, we demonstrate that a de La Vallé Poussin Theorem does not hold in the general setting of vector lattices.