useChat / AbstractChat: Safari's "Load failed" network error is not detected as a disconnect (isDisconnect false, resumable state dropped)

Finding: In vercel/ai issue #22083, the reporter says that with ai 7.0.128 (also seen on 7.0.127 in production), a Safari/WebKit network failure during a streaming useChat/AbstractChat request surfaces as TypeError 'Load failed'. It is not classified as a disconnect: onFinish gets isDisconnect false and resumableStreamState is cleared instead of kept (https://github.com/vercel/ai/issues/22083). This is an external report; KFA did not reproduce it. Reported mechanism: AbstractChat marks a TypeError as a disconnect only if its lowercase message contains 'fetch' or 'network'. The reporter's Node script simulates a mid-stream TypeError with several messages. Per the report, 'Failed to fetch', 'network error' and Firefox's 'NetworkError when attempting to fetch resource.' yield isDisconnect true, while 'Load failed' yields false (https://github.com/vercel/ai/issues/22083). The simulation uses a mocked fetch in Node, not a real Safari session. Reporter's production observations: over 7 days, 36 'network error' and 1 'Failed to fetch' events were treated as disconnects and retried or resumed. 3 'Load failed' events on iPhone iOS Safari were not, and the server reportedly finished the response while the client showed an error needing manual reload (https://github.com/vercel/ai/issues/22083). These counts are reporter-supplied and unverified. Contributor comments: a contributor-association comment says the bug was reproduced against main at package version 7.0.128. It says 'Load failed' gave isDisconnect false and a terminal error state, while the 'network error' control resumed correctly (https://github.com/vercel/ai/issues/22083#issuecomment-6001421620). A later contributor-association comment describes a root cause matching the reporter's analysis and says a bugfix PR #22102 adds the 'Load failed' wording to disconnect detection, with a regression test and patch changeset (https://github.com/vercel/ai/issues/22083#issuecomment-6004196806). These are not confirmations from a maintainer. Status: the issue is CLOSED, but the supplied input does not show that PR #22102 was merged or which released version contains it. Closure alone is not proof of a shipped fix. Users should check the project's release notes or changelog themselves before assuming a fix. The reporter also suggests classifying errors by origin (a TypeError from transport fetch or body reading) rather than by message text; this is a proposal, not a confirmed design. Diagnostic takeaway, supported only as reported: if Safari/iOS users on these versions see 'Load failed' with isDisconnect false and no resume, the message-text check is the reported cause. No workaround is documented in the sources, and none is claimed.