Trace does not include server load spans in dev environment

[joemmalatesta]

Is there an existing issue for this?

• [X] I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• [X] I have reviewed the documentation https://docs.sentry.io/
• [x] I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/sveltekit

SDK Version

8.11.0

Framework Version

SvelteKit 2.0.0

Link to Sentry event

No response

SDK Setup/Reproduction Example

// src/hooks.client.ts
import { handleErrorWithSentry, replayIntegration } from '@sentry/sveltekit';
import * as Sentry from '@sentry/sveltekit';

Sentry.init({
	dsn: {DSN}
	tracesSampleRate: 1.0,

	// This sets the sample rate to be 10%. You may want this to be 100% while
	// in development and sample at a lower rate in production
	replaysSessionSampleRate: 0.1,

	// If the entire session is not sampled, use the below sample rate to sample
	// sessions when an error occurs.
	replaysOnErrorSampleRate: 1.0,

	// If you don't want to use Session Replay, just remove the line below:
	integrations: [
		replayIntegration(),
		Sentry.feedbackIntegration({
			// Additional SDK configuration goes in here, for example:
			colorScheme: 'light'
		}),
	],
});

// If you have a custom error handler, pass it to `handleErrorWithSentry`
export const handleError = handleErrorWithSentry();

// src/hooks.client.ts
import { sequence } from "@sveltejs/kit/hooks";
import { handleErrorWithSentry, sentryHandle } from "@sentry/sveltekit";
import * as Sentry from '@sentry/sveltekit';

Sentry.init({
  dsn: {DSN}
  tracesSampleRate: 1.0,

  // uncomment the line below to enable Spotlight (https://spotlightjs.com)
  // spotlight: import.meta.env.DEV,  
});

// If you have custom handlers, make sure to place them after `sentryHandle()` in the `sequence` function.
export const handle = sequence(sentryHandle());

// If you have a custom error handler, pass it to `handleErrorWithSentry`
export const handleError = handleErrorWithSentry();

Steps to Reproduce

repo available at https://github.com/joemmalatesta/osumon.

When running in a development environment using npm run dev, the spans for requests made in load functions for routes like src/routes/v1/[username]/+page.server/ts are not included unless manually instrumented using Sentry.startSpan() This image shows the trace for a load function in a development environment.

However, this is not the case in production or running a prod environment locally using npm run build and npm run preview. In this case, the spans will be sent as expected (as seen in expected result)

Expected Result

Actual Result