So I'm not sure why it works, but I noticed that on another page I wasn't using an H6 tag specifically, I had added it to a label. For some reason, this spaces it perfectly. An h6 tag, even with mb-0 on it, still top justifies the text.
@Html.Label("Active Workflow", new { @class = "h6" })
With just the h6 tag, the column is 23 pixels in height, with the label it's 26.
