As per POWO, Trifolium angustifolium subsp. angustifolium is a synonym of Trifolium angustifolium. All other subspecies have already been granted their own specific status, leaving this nominotypical subspecies redundant: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:522858-1
Unintended disagreements occur when a parent (B) is
thinned by swapping a child (E) to another part of the
taxonomic tree, resulting in existing IDs of the parent being interpreted
as disagreements with existing IDs of the swapped child.
Identification
ID 2 of taxon E will be an unintended disagreement with ID 1 of taxon B after the taxon swap
If thinning a parent results in more than 10 unintended disagreements, you
should split the parent after swapping the child to replace existing IDs
of the parent (B) with IDs that don't disagree.