Related for Nedarim 84:2

3:11 Rabbi discusses the scenario of one who consumes untithed produce that belongs to another individual. According to his opinion, that person must reimburse the value of the untithed produce, including the would-be tithes. In contrast, R. Yosé b. R. Judah asserts that repayment should only cover the cost of the unconsecrated produce. If an Israelite consumes his own untithed produce, he is answerable to heaven. Yet, the priest has no claim against him, as stated in Num. 5:9. The priests can only claim produce after tithe separation. This rule also applies to a Levite that consumes his share before tithe separation.