I have created a funnel in google analytics with conversion rate 2.96% and abandonment rate 92.66% (Sum 95.62%). I would expect their sum to be 100%, do I miss something?
Possibly because you have marked the first step of your funnel as "required". While this seems to be "recommended practice", it can produce a discrepancy between Conversion Rate and Abandonment Rate. According to The Google Analytics Conversion Funnel Survival Guide entry on Neil Patel's blog:
Abandonment Rate Is Not Always the Inverse of Conversion Rate
If your Funnel Conversion Rate is 44.96% as above, you might expect the Abandonment Rate to be 55.04% for a total of 100%, but this is not usually the case if your first funnel step is marked as required. While the Funnel Conversion Rate in the Funnel Visualization report respects the first-step requirement, Abandonment Rate does not; hence, the seeming discrepancy.
As I read that article, if it is possible to get to the "goal page" without having passed through the required "first step" of your funnel, this:
Would decrease the Abandonment Rate (because the goal was achieved, irrespective of whether the first page was viewed), but:
Would not alter the Conversion Rate (precisely because the first page was not viewed).