Firefox focus order

Hi, i’m currently working in a vaadin web that has a few components, a tabsheed with a variable amount of tabs with several components in each tab and a few more components at the bottom. I’ve created a way to handle that every component is created with a correct index sequence number in a way that the elements at the top are selected first, then the elements in the visible tab and finally the elements in the botton part of the page. The thing is that this works perfectly with chrome and edge, but not with Firefox ESR 38.5.2. Inspecting the dom i can see that the index order is still on the elements but when pressing tab only the top and bottom elements are focused, the rest of the elements in the page are avoided. The only special ciscunstance about the tab component is that is refreshed with the appropiate tabs after the page has been loaded.

Any tips? Or should i try to report it as a bug for that firefox version?