Plarium is trying to fix it. Here is the first part of their response to the report I made:

"Plarium Support Team

Dear Jarl,

Thank you very much for providing us with this information. We are aware of the situation and are working to solve it. We apologize for the inconvenience caused."

I guess it's not a simple fix but it would have been nice if they could have posted something like that in the forum themselves. But then I suppose people would then be asking when it will be fixed.

This has been an occasional nuisance for a long time, but the past several days it's been out of control. The majority of Invader's Lairs and Ghost's Shelters that I've tried to attack have given the "The location is no longer at the coordinates" error. And they're still on the board days later. :-(

Good day, Jarls!

Thank you for informing us! Our specialists managing to solve it, thanks to your help.  

We do our best to resolve this situation as soon as possible.

We apologize for any inconvenience caused and thank you for your understanding and patience!

The problem seems to be fixed in the kingdoms I've looked at.

We are glad it's resolved! If you have any other issue in future, please do not hesitate to contact us. 

Thanks in advance.