'qa-topic-tip' Ember is not defined error

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Thanks for reply.
I have commented all third-party plugins in app.yml, wrote EMBER_VERSION: 5 in ENV section and rebuilt Discourse. Now i have following error in JavaScript console:

Uncaught (in promise) ReferenceError: Ember is not defined
    <anonymous> media-overlay.js:15
    exports loader.js:106
    requireModule loader.js:27
    Ember 8
    initialize component-templates.js:44
    eachThemePluginTemplate component-templates.js:95
    initialize component-templates.js:32
    runInstanceInitializers Ember
    each dag-map.js:191
    walk dag-map.js:120
    each dag-map.js:66
    topsort dag-map.js:72
    Ember 4
    invoke backburner.js.js:280
    flush backburner.js.js:197
    flush backburner.js.js:358
    _end backburner.js.js:798
    _boundAutorunEnd backburner.js.js:523

And the same Loading animated picture. What’s wrong?

UPD: Safe mode with safe_mode=no_themes%2Cno_unofficial_plugins works.