Taggify generates a synthetic point tag with a scope of just within the query line. What that means, basically, is that both the taggify expression and the other expression have to be part of the same query line. If you have them split out into 2 query lines, the second query line won't "know" about the synthetic point tag.
BTW, since we may all be in different Wavefront environments, it's probably helpful to post the full queries in addition to providing links.
HTML is the language of the Angular template. Almost all HTML syntax is valid template syntax UPSers. The <script> element is a notable exception; it is forbidden, eliminating the risk of script injection attacks. In practice, <script> is ignored and a warning appears in the browser console. See the Security page for details.