Integrated accounts are filterable but not accessible

[ArekWilczynski1996]

Bug Description

Hello,

I am experiencing multiple issues with users created via the SDK using the capture method, which I have previously described in support tickets. However, I have not received any response for over a month.

As a live example, the integration appears to complete successfully, returning all success status codes. However, when I attempt to retrieve information about the integrated user, I receive a "Person not found" message. I can filter for the user using all assigned properties from the integration, but I cannot access their full user profile.

Previously, I encountered an issue where approximately 10% of the data was not integrating properly—I received a 200 status on the callback, but the users did not exist and could not be filtered at all. However, this issue disappeared in the last integration.

I am following all documented limits and capturing all status codes other than 200. So far, I have only encountered four such cases, which are unrelated to this issue.

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/01958003-00d3-7e0e-9a96-ba594ac7035b?t=43
Admin: http://go/adminOrgEU/019197e1-0cdf-0000-704f-9245dd99e579 (project ID 31056)
Sentry: http://go/sentryEU/31056

Debug info

- [ ] PostHog Cloud, Debug information: [please copy/paste from https://us.posthog.com/settings/project-details#variables or https://eu.posthog.com/settings/project-details#variables]
- [ ] PostHog Hobby self-hosted with `docker compose`, version/commit: [please provide]
- [ ] PostHog self-hosted with Kubernetes (deprecated, see [`Sunsetting Kubernetes support`](https://posthog.com/blog/sunsetting-helm-support-posthog)), version/commit: [please provide]