Sometimes web extensions do not load in Safari, including 1Password for Safari

This has to do with Apple’s Launch Services implementation and extension framework, so it will keep happening to users from time to time, until, Apple fixes their bug, likely after multiple extension developers lean on them to do so.

Which with Apple's 'best in class' obtuse bug count avoidance engineering team, means you give them a bug with precise steps to reproduce, it languishes for weeks, then some Apple engineer replies to your bug clearly not having read it asking you to reproduce it even though they know they've implemented nothing to fix it. Because, hey, why should the world's largest tech company by market cap field an appropriately sized QA team, with an appropriately scoped test matrix, and a lab in which to reproduce bugs, when they can push that cost and bother back out on customers and third party developers.

All that is to say, let's cut 1Password some slack on this, and feel free to hit Apple up with a support ticket when it happens.