I noticed that iNat has both Nymphalis vaualbum and Nymphalis l-album. Apparently these are synonyms and Nymphalis l-album is the valid name http://butterfliesofamerica.com/US-Can-Cat.htm
Pelham, J. P. (n.d.). A Catalogue of the Butterflies of the United States and Canada by Jonathan P. Pelham. Butterflies of America. Retrieved September 25, 2013, from http://www.butterfliesofamerica.com/US-Can-Cat.htm
(Link)
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.
Seems to be pretty disputed which name is valid, but Fauna Europaea also recognizes Nymphalis vaualbum (www.faunaeur.org/full_results.php?id=441669). See also www.lepiforum.de/lepiwiki.pl?Nymphalis_Vaualbum