Button element is changing the URL I’m using for a link

I’m trying to use a URL on my site that will pass UTM parameters if they are present. This is working fine for “regular” text links, but when I try to use this link for a GO button, the URL I enter is not maintained.
You can see this on my staging site on this page:
https://test.dnastar.com/software/lasergene/genomics/

Look at the button under the intro paragraph that says FREE TRIAL DOWNLOAD.

The URL I’ve entered for the button is /cb/f-reg-submit.aspx?utm_campaign=[utm_campaign]&utm_source=[utm_source]&utm_medium=[utm_medium]&utm_content=[utm_content]&utm_term=[utm_term]

However, the link being displayed and used on the actual webpage is:
/cb/f-reg-submit.aspx?utm_campaign=%5Butm_campaign%5D&utm_source=%5Butm_source%5D&utm_medium=%5Butm_medium%5D&utm_content=%5Butm_content%5D&utm_term=%5Butm_term%5D

Notice the text link just above the buttons. It uses the same URL and works as expected.

Can you help me figure out how to address this?