The Fleet list is the only endpoints route on the bare blueprint prefix, so it registered as /api/endpoints/ while the SPA calls /api/endpoints. With strict_slashes on, Flask 308-redirects to add the slash; behind the /shopdb reverse proxy (IIS ARR) that redirect Location drops the path prefix, so the list call fails while suffix routes like /api/endpoints/<id> keep working. That is why a healthy, reporting endpoint showed on its PC detail page but never in Fleet. strict_slashes=False makes both URL forms resolve directly and removes the fragile redirect.
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