In Europe (at least the Hilton chain hotels I've visited within Europe, which I consider to be a fair few), the only time I have been moved after I have done OLCI is when they have upgraded me further (potentially when they have been full and / or needed the room I had selected for service recovery with someone else). Usually though, when I have OLCI they never move you (at least as a diamond).
Not sure if the OP was in the US but that could be a difference to note as well. (I'm not having a go at the US hotels, simply seems that there are more status guests and the value of said status is worth less in the USA).
Safe travels, hope you have better luck with OLCI and status being valued by hotels in future.