Answer: The Rema (OC 135:2) writes that if a shul didn’t manage to lein one week, they should catch up the following week by reading the omitted parsha. The Gra (OC 135:2) comments that this is akin to one who skipped a tefilla who can later make it up. Following this, the Mishna Berura (Biur Halacha 135:2) writes that if one purposely skipped leining one may not be able to make it up. The Mishna Berura (135:7) writes, however, that a shul only needs to catch up if the majority of the congregants didn’t manage to hear the leining.
When Pesach begins on a Shabbos or Shavuos begins on a Friday, the last day of Yom Tov in chutz la’aretz is also Shabbos while in Eretz Yisrael it is already isru chag. This discrepancy causes Eretz Yisrael to be one parsha ahead of chutz la’aretz. The Piskei Teshuvos (285:9) writes that one who travels to Eretz Yisrael during this time should ideally find a minyan that will read the missing parsha allowing one to catch up. R’ Gavriel Zinner (Nitei Gavriel, Pesach 40:5) writes that if this isn’t feasible, then one fulfills one’s duty of listening to the local leining.
R’ Nosson Gestetner (Lehoros Nosson 3:13:8) writes that even though when one returns to chutz la’aretz they have already heard that leining, one needs to listen again, as one shouldn’t go for three days without hearing leining.
In conclusion, if one can easily daven in a minyan where they will catch up the leining, one should do so. Otherwise, one should listen to the leining there and listen to it again upon their return.