As described, this is not a bug; it is working as designed. For consistency of style and to reduce vertical space within a single wiki page: tags, feeds, and categories are grouped into the same vw-block-box, with a single border around them all. That is the designed behavior.
The only issue I see from your OP is that in the default style the .tagBlock has a margin in addition to the padding for the container. The interior margin should be suppressed; this is fixed in the next release.
Additionally, there are some discrepancies in how the various labels in vw-block-box are displayed (when compared to other labels within the same vw-block-box), which are now fixed.
In order to fix the discrepancy, the wiki's tag block can no longer use the helper_tag_list template. Rather, a modified version of the template is now coded into vw_node_tags. Unfortunately, most standard classes (tagBlock, tagList, etc) must remain on the wiki tag-list in order for XenForo to recognize it as editable.
If you use a custom style which adds unwanted borders inside vw-block-box, you should be able to remove the extra borders by using custom CSS. I have added additional classes in the tag block for the next release to further assist with this.
If you do not wish any border around categories+tags+feeds, feel free to modify the existing style property for vw_box (Wiki Pages > Tag Boxes). I have updated this property in the next release to allow for font-size adjustments.
Marking this as fixed in the next release.