Positive tabindex
What it means
A tabindex greater than zero pulls an element to the front of the tab order, ahead of everything in document order. One of them rearranges keyboard navigation for the whole page, usually in a way nobody intended.
How to fix it
Use tabindex="0" to make something focusable in its natural position, or -1 for something only script will focus. If the tab order is wrong, fix the order of the markup rather than overriding it. WCAG 2.4.3.
Finding it in CrawlStat
After a crawl, open Issues and pick Positive tabindex. Click Show all in Pages to filter the Pages table to the affected pages, or Export affected to hand the list to whoever owns the fix. Audit ID: a11y_positive_tabindex.