This study investigates the hypothesis that non-isomorphic syntax-semantics mappings pose a greater challenge for non-native (L2) than for native (L1) speakers, focusing on a previously understudied phenomenon. We carried out an antecedent judgment task with L1 German and L1 Russian-speaking, proficient L2 learners of German to examine Condition C connectivity effects in German pseudoclefts. Binding Condition C constrains the interpretation of cataphoric pronouns such that they cannot be interpreted as coreferential with a referential expression within their scope. In specificational pseudoclefts such as "What she liked was Jane's office," Condition C effects can be observed in the absence of the required structural configuration, indicating that these effects result from the computation of a non-isomorphic semantic representation. For superficially similar -- but semantically different -- predicational pseudoclefts, no connectivity effects are expected. While the L1 speakers' judgements showed the expected selective Condition C effect, the L2 speakers showed an across-the-board effect, with their antecedent judgements based on surface-level cues to cataphoric pronoun resolution and not affected by the semantic differences between the two types of pseudocleft. These findings support the claim that establishing syntax--semantics mappings is more difficult in a non-native than in a native language if there is no one-to-one correspondence between form and interpretation.