I use VS Code and felixfbecker.php-debug extension.
I run project that uses Smarty template engine.
When I enable step debugging (no breakpoints) xdebug outputs lots of notices like this:

<?xml version="1.0" encoding="iso-8859-1"?><notify xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug&quot; name="error"><xdebug:message filename="file:///***.tpl.php" lineno="240" type="Notice"><![CDATA[Undefined index: attrs]]></xdebug:message></notify>

These messages continue appearing even when php script is finished. If I enable xdebug profiling, I can see that profiling output file stops growing, so it means php script finished its work. But xdebug still generates output notices and server can't send response to browser until this process end.

Enabling/disabling xdebug logging or profiling doesn't change anything.

This issue doesn't appear on xdebug v2.x.x, but appears on 3.x.x.

xdebug config:

xdebug.client_host = "127.0.0.1"
xdebug.client_port = 9000
xdebug.idekey="vscode"

xdebug.log_level = 0
xdebug.mode="debug"

xdebug.start_with_request="trigger"
xdebug.trigger_value=""

xdebug.force_error_reporting = 0
xdebug.force_display_errors = 0