Captivate 10 - Hyperlinks & Viewports

I have a project in Captivate 10 where we are building a responsive project. In it we have some hyperlinks,

In the published output (HTML 5) these work fine for the desktop view (the largest of the 4 viewports). However, when shrunk down and viewed in the lower ports the links stop working. The hand is present, but no opening of link happens.

I have done the following so far:

1. Tested in different courses and on different pages - consistently fails
2. Tested with both creating new hyperlinks and editing existing hyperlinks - both fail
3. Deleting existing hyperlink and re-creating it (rather than editing the url) - consistently fails
4. Deleting the text and recreating full content - - fails
5. Deleting the textbox and re-creating textbox & content - fails
6. Verified that the link is being carried down through all the lower view ports - it is always there and present, it just doesn't work when published
7. Checked using developer tools (raw code included below) - they both look the same (no missing code)

For a particular page type where the link was central to the user journey, I ended up creating a shape button to place over the top of the dysfunctional link, this workaround doesn't work for links within bodies of text as the size and position of the text changes post publish (this movement can be quite significant on narrower viewports)

Any ideas or should we just not use hyperlinks?

-Bonus question-

Why is captivate not using the regular <a> tags for links in html 5 output?

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example code difference between working and not working on same resolution:

works --  <span style="text-decoration:underline;cursor:pointer;" onclick="cp.hyperlinkClick('HL447893_767_0');">Link text</span>

broken--  <span style="text-decoration:underline;cursor:pointer;" onclick="cp.hyperlinkClick('HL449689_767_0');">Link text</span>