When selecting one object and changing current layer, every object is selected and moved?

[nshupeFMPE3]

A strange bug has cropped up with projects done with one of our drafters. Some how when we try to work on something that was made with his templet, when we try to select one of our blocks and use the layer drop down in the ribbon to change that single blocks layer, something starts selecting everything it can and setting everything to that layer. 
When we take the blocks and everything from the drawing and transplant it into a different persons templet, everything works fine? 

Any ideas of what might be going on would be greatly appreciated. We do have custom plugin tools and lisp files but I develop those and there isn't anything in there that would do that. Also we are all on the same version of these tools so moving from one templet to another wouldn't fix that issue if it were the custom tools.

[Valentin_CAD]

@nshupeFMPE3 ,

Try the suggestions from this link:

• How to repair corrupt AutoCAD files

[ChicagoLooper]

Go to the bad drawing. ‘Accidentally’ select all blocks even though you’re only trying to select an individual block. Take a scree shot capturing both modelspace and the Properties Palette then upload the screen shot. 

[pendean]

Was your "one object" part of a group, or a block, or ...?

Since you used the word "we" that also means everyone over here can replicate the issue in that user's file(s): care to share a DWG file with the problem for everyone to try?

[jporter]

Along the lines with @pendean. . .it does sound like a group to me.  Are you able to post the drawing and or template?  Or maybe make a Screencast for us to view?