Media Manager Trim Venice Cam files

I somehow got R17 to actually trim not transcode a timeline full of MXF OP1A CVX-OCN LT files
from the Sony Venice Camera. I set Media Manager to copy my timeline, selected Used media and trim with handles. It worked once but now the Relink to new files button grays out.

First time I got trimmed files appended with S000, S001, S002 etc. and a relinked timeline. Problem is I don't know what I did that made this work. Only worked once, same timeline.
Anyone know about this?

thanks