Why doesn't modx register scripts via regClientScript()?

Question

MODX

Hi all! It's been a long time since modx site wants to register anything via regClientScript(), regClientCSS() or regClientStartupScript(). Just nothing happens. And I noticed this when I tried to raise ajax pagination through pdoPage. I tried disabling all plugins, suddenly some kind of interception is in progress. I tried to connect scripts through my plugin and my snippet. Nothing works. Tell me, please, where can I dig?

ps Where possible, I connected everything manually. But pdoPage doesn't want to start.