Since you already expanded the logical volume, the extents are already being used by that LVOL.
You can check that with lvdisplay -m <lvol in question> .
After resize2fs, did the mentioned filesystem increased in size (even partial?)
If yes, you will need to put the new disk inside, and use pvmove to move the extents from that disk to new one.
After that you can use vgreduce.
Can you please post the output of lvdisplay -m LVOL vgdisplay -v VOLUMEGROUP