replace block moves the symbol in the block location help!

I have blocks with several attribute tags and layers. The problem I am having is somehow when I go to replace the block with a different one the attribute tags stay in the right spot but the symbol acts like it looses its coordinates and comes in a different spot. I cant seem to fix it. When I zoom all it block editor it zooms like I have a symbol way off the mark, but I don't. Any help greatly appreciated.

If I attsync it moves the attributes back to the symbol but it is moved in the drawing.

it sounds like the base is being redefined in a different position to where it is in the original block.

I would rename the exisiting block and import the new block and examine them side by side, noting where the INSERT point is in each of them.