Hello, we've looked into your file. We don't believe there is a bug as you have merged Advanced Nation Data for 6 different nations and the editor only allows for testing in the one specific Advanced Nation currently loaded (in this instance Spain).
The result of this is that you can bypass errors and the verification process for the other 5 nations and then run these untested and unverified leagues in-game.
You have also replaced the English, French, German, Italian, Spanish and Dutch leagues with his Continental super leagues. This means we have teams playing in a domestic league from the wrong country/continent and other clubs have had their country/continent changed. It also means that other competitions do not have the required teams.
Furthermore, countries like England will have a lot of complicated underlying rules/regulations that have not been taken out such as ESC work permits and Brexit and now apply to teams it was never supposed to. There are likely to be numerous errors that have been bypassed, not to mention a number of active leagues (e.g. Portugal) have been broken.
We can't go in and check every detail as you have made changes in the thousands. Instead, our advice would be this:
1. Create new competitions, do not replace existing ones.
2. Create these competitions within a non-active Nation (ideally one which matches the continent of the participating clubs)
3. When removing teams from an existing competition, either replace them or reduce the number of teams in that competition (Ideally replace).
4. Use a different .fmf file for each league/nation (will be easier to test then can merge when verified).