https://wccftech.com/apple-has-reissued-watchos-5-beta-1-to-developers-after-temporarily-removing-it-last-week/

Apple seeded the first developer beta of watchOS 5 after its WWDC keynote. The firmware update brought quite a handful of notable updates to the smartwatch such as the new workout models, Walkie Talkie, Siri updates and much more. However, after Apple released the first beta watchOS 5 beta, developers who have installed it on their Apple Watch started running into issues. This made Apple temporarily remove the beta 1 from its developer website. Now, the company has reissued the update.

As we have mentioned earlier, Apple removed or pulled the watchOS 5 geta from its website because it could lead to some unexpected issues. The issues arise in the update process. Apple only temporarily removed the beta in an attempt to correct the issue and release the stable build.