This study investigates the processing of structurally ambiguous relative clause (RC) constructions in Japanese by Persian-Japanese learners, examining the influence of their native language (L1) on second language (L2) processing. It challenges the universality of parsing strategies through a self-paced reading (SPR) task. The results indicate a preference for High Attachment (HA) and a stronger tendency towards NP-high when it's an animate noun, in both Persian and Japanese. Descriptive analyses further revealed a shift from Low Attachment (LA) to HA among native Japanese speakers, suggesting unforced revision. However, there was an absence of a clear animacy effect on their preference. These findings suggest parallel interactive mechanisms in sentence processing and the transfer of syntax and semantic information from L1 to L2. Moreover, the study underscores language-specific differences in sentence processing, emphasizing the impact of language dominance in cross-linguistic transfer and contributing to our understanding of bilingual sentence processing.