I updated the Flarum from beta16 to 1.0.2. Update was without errors. I done
php flarum migrate and
php flarum cache:clear commands. After, all discussions are not displayed and show just connected user in userlist. No errors display in console. All discussions are present in database!
I disabled all extensions from Admin page. All discussions was displayed. One by one, I enabled just Flarum extensions. Last extension was
flarum-tags. After this extension, all discussions again diappeared from IndexPage.