Sad but true (or as true as taxonomy gets). This is Esslinger's underlying citation: McCune, B., R. Rosentreter, T. Spribille, O. Breuss & T. Wheeler. 2014b. Montana Lichens: An Annotated List. Monographs in North American Lichenology 2: 1-183. Northwest Lichenologists, Corvallis, Oregon.
Esslinger, T. L. 2015. A Cumulative Checklist for the Lichen-forming, Lichenicolous and Allied Fungi of the Continental United States and Canada. North Dakota State University: http://www.ndsu.edu/pubweb/~esslinge/chcklst/chcklst7.htm (First Posted 1 December 1997, Most Recent Version (#20) 19 April 2015), Fargo, North Dakota. (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.