There may be a time when you are looking at an overview of your blog post data in the Campaigns tool and it doesn't seem that the CTA conversion rate is being calculated correctly.
The blog post overview section shows Views, CTA clicks, and CTA conversions, as shown here:
The CTA conversions percentage number is calculated by dividing the CTA clicks number by CTA views (for CTAs on the blog posts in the campaign) and not by page views. The conversions rate is calculated using CTA views instead of page views to give a more reliable conversion rate, as some pages may not include CTAs. Calculating this number using the page views metric would not be an accurate reflection of how many times a CTA was seen and then clicked.