All my pinned tabs have disappeared in Safari

It's possible that this could be a bug in Safari, but there are also other possible explanations. Here are a few things you can try to recover your pinned tabs:

1. Check if the tabs are hidden: Sometimes, Safari can hide your pinned tabs behind the address bar or the sidebar. Click on the small arrow icon next to the address bar or the sidebar to reveal hidden tabs.
2. Check if Safari is set to open new windows instead of new tabs: In Safari's preferences, go to the "Tabs" tab and make sure "Open pages in tabs instead of windows" is selected.
3. Try restoring a previous session: If you recently closed Safari or restarted your computer, you may be able to restore your previous session, including your pinned tabs. Go to the "History" menu and select "Reopen All Windows from Last Session".
4. Check if the tabs are synced: If you have enabled iCloud syncing for Safari, your pinned tabs may be synced across all your devices. Check if you can access your pinned tabs on another device that is synced with iCloud.

If none of these solutions work, it's possible that your pinned tabs have been lost due to a bug or some other issue. In this case, you may need to manually recreate your pinned tabs.