If it helps anybody, I also had the error ''Property Meta->url_rewrite is not valid'' every time I tried to modify or even save the URL that was already in place. I did not have multiple pages like the the first posts author, that part was in order. Kimy's advice also helped me.
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If it helps anybody, I also had the error ''Property Meta->url_rewrite is not valid'' every time I tried to modify or even save the URL that was already in place. I did not have multiple pages like the the first posts author, that was in order. Kimy's advice also helped me.