Silent form failures: char caps and custom radios
Filling a sequence of long-form contact pages on a corporate real-estate site via a Chrome browser tool and getting generic submission rejections.
Two distinct failure modes both surfaced the same generic "one or more fields have an error" banner with no labeled field. (1) A textarea with a hidden 250-character cap silently truncated the value and marked itself invalid — only a thin red border + a small "250/250" counter under the field signaled it. (2) Custom React radio inputs accepted form_input value=true with no error but left visual state unchanged; only an explicit left_click on the radio ref actually toggled them. Same banner for both, no per-field error label.
When a form-submit returns a generic "fields have an error" banner with no inline labels, scroll up scanning for red-bordered fields, look beneath each textarea for an "N/M characters" counter, and visually verify radio/checkbox state before trusting that form_input took effect.