I've had this occur on a number of WordPress sites over the years. What happens is that the "Thank you for creating with WordPress." footer ends up part way up the page. Where I notice is is on the /wp-admin/plugins.php page.
It occurs with all plug-ins disabled, and when using a default WP theme.
When I investigate the underlying CSS, it seems to me it's because it's container #wpfooter is position: absolute;. In my opinion it should be position: relative. Changing it to that on the fly certain resolves the problem, with it returning to its position at the bottom of the page.
What's perplexing to me is that the declarations for #wpfooter are coming directly from the relevant wp-admin stylesheet, as opposed to something custom which is over-riding things.
Can anyone help my understand why this might be occurring?
Here are relevant screenshots:
The issue itself
The wp-admin CSS that's causing this
The HTML structure and relevant CSS
