By doing that you have excluded theme plugins from templates compilation. This is temporary solution until next recompilation.
There is an issue with PHP8 uncatchable error, which was deprecated in PHP7.4. Some theme plugin hooks use trick with parent template function overloading in addition to documented hookData() method:
public function includeCSS()
{
\IPS\Output::i()->cssFiles = array_merge( \IPS\Output::i()->cssFiles, \IPS\Theme::i()->css( 'somePlugin.css', 'core', 'front' ) );
return parent::includeCSS();
}
As a workaround you can fool the interpreter by changing
return parent::includeCSS();
to
return \call_user_func_array( 'parent::' . __FUNCTION__, func_get_args() );
The difficulty is that these new errors are not catchable by error handler, so you can't know which hook file is causing them. This often happens with this plugin https://invisioncommunity.com/files/file/9966-back-2-top/ and this app https://invisioncommunity.com/files/file/7940-iawards/