Objects are not valid as a React child
This message shows up in 2 different situations. Pick the one that matches yours:
- A Hyperlink column takes an object, not a stringIt reads back as { Description, Url } ([object Object], React #31) and a plain string fails the whole save with 400; one helper each way, 255-character address limit, scheme allowlistCause and fix →
- Minified React error #310 (and friends) — the SPFx debugging cheatsheet#310/#300/#321/#31/#185 decoded for SPFx debuggingCause and fix →