BugGuide seems like the most applicable authority here given the North American distribution, and they treat this as a subspecies of H. columbia. See https://bugguide.net/node/view/116365
BugGuide cites ZooKeys 38 doi: 10.3897/zookeys.38.383 but does not apply the changes. There is an extensive justification for H. gloveri ex H. columbia in appendix A17 that's several pages long. I would suggest keeping H. gloveri as a distinct taxon based on that work.
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.
BugGuide cites ZooKeys 38 doi: 10.3897/zookeys.38.383 but does not apply the changes. There is an extensive justification for H. gloveri ex H. columbia in appendix A17 that's several pages long. I would suggest keeping H. gloveri as a distinct taxon based on that work.