Sorry we find some but very few, I think the respawning time is very long.

 Could you please check if there is no issue ?

As far as I know there are only very few (8?) (each?) at a time. I think I saw they respawn every 3h.

Plarium's Discord server at https://discord.gg/rdyfTBT has been very helpful and timely on this.

I have seen that they are all over - not just near the ES. e.g. Out on the edges.

I could find tile 8 first day and second, after that only a very few and nothing. Like I did not understood I asked Plarium to know how it is working and the answer is : These locations appear on Kingdom Map for 5 days or until they are fully yielded. Based on the availability of other elements on the kingdom map, these locations may appear all at once or gradually. Once all set resource locations are yielded they stop respawing.

So we can be sure it will be war in Kingdom after war against 3 other Kingdom for having the benefit of these tiles who also offers more that rss with ingots or sulfurum.

Thank you VERY MUCH for posting their response. That is most helpful.

So ... there are only every going to be X number of them, and once they are gone, they are gone.

So ... get them before your OvO enemy does, and be ready to hit them when they try.