I have a settlement in mirkwood that has basically 2 settlement holdings in the county, i upgraded one and went to upgrade the other just for the button to be greyed out, I am not sure if its a bug or if its just i upgraded the wrong stuff etc, not sure if anyone else came across this and if there is a fix

*edit* Just adding on the county is Gwathrad in south of mirkwood, the holding is elenechor and even when abandoning Gwathrad settlement and recolonising it just comes back again as a settlement holding you cannot abandon