@randomhammer
Hi, I just run into this, But I fixed it by the followings:
1. export **1pif** from 1password
2. select **CSV** not **1PIF** when u wanna import with **1PIF**
3.select your **1PIF** file
4.back to step 2 and select **1PIF** this time
5. click **continue** and it's done.
It looks like a bug on 6.4.2 on Mac App Store @Garima Singh @Pratyush Sharma