FORCDK-FIELDSET-001
Warned by forty-cdk/fieldset, in development builds only.
[forty-cdk/fieldset] FORCDK-FIELDSET-001: A [forFieldset] is labelled by a single [forFieldsetLegend], but {registered} are registered.Cause
They share one legendId, producing duplicate DOM ids and unstable aria wiring.
Fix
Keep one [forFieldsetLegend] per [forFieldset].
Where it comes from
projects/forty-cdk/fieldset/src/fieldset.ts:163
Read the fieldset documentation
A value in braces is filled in when the message is reported, so the sentence in your console names the piece, input or value that failed.