Recurring 'Failed to fetch' on /practicas/nueva - same frame, Android Chrome, 5 occurrences since June

Recurring client-side TypeError 'Failed to fetch' on /practicas/nueva. NOT transient network and NOT a new signature - errscan surfaced the 2026-08-18 19:19:46Z row as '1x new signature', but measured against appEvents there are 7 'Failed to fetch' rows since 2026-06-17, FIVE of them on /practicas/nueva (2026-06-17, 07-08, 07-14, 07-15, 08-18). Concentration is the evidence: every one is errorName='TypeError', every one is Android Chrome (150/151), and every one dies at the SAME minified frame 'at I' in the page chunk - the chunk hash changes across deploys (0wvhq5ri18uyu -> 2r2snb12eb8ap) while the frame does not, so it is one surviving code site rather than a build artifact. Random client network loss does not cluster on one route + one platform + one frame for two months. User-recoverable and therefore unreported: two appEvents action='uploaded' info rows land at 19:21:55Z and 19:21:57Z, ~2min after the failure, so that user retried and succeeded. Impact is on the practica-creation path, the app's primary flow. NOT YET IDENTIFIED: which fetch 'at I' resolves to - the stack is minified and no sourcemap was consulted. That is the next step and explicitly not a conclusion. Instrument note for whoever picks this up: the payload lives in appEvents.errorName/errorMessage/errorStack, NOT appEvents.message (message is NULL on every one of these rows - a query selecting 'message' makes them look contentless). Writer is src/app/api/internal/log-error/route.ts, scope='rejection' -> action='clientUnhandledRejection'.