You're using the XCLIP command to crop an Xref or block, and you're noticing some unwanted lines that are projecting along the XCLIP areas.
You may have tried to delete these lines projected along the XCLIP area but found that doing so also erased objects in the drawing.
The XCLIP areas have somehow become associated with objects in the actual drawing.
The XCLIP command is a method of cropping an Xref or block, hiding all objects outside a selected border. More information
Run the XCLIP command again. This time, select only the XCLIP boundaries you wish to remove.
You can use the CTRL + A keys to select all objects in your drawing, then hold SHIFT and deselect all the objects you want to keep.
After you've selected the objects you want to remove, use the Delete option. The XCLIP areas will be removed, and the content initially connected to that XCLIP will remain.
If you simply select the XCLIP areas and use the Erase or Delete key on your keyboard, the objects tied to those XCLIP areas will also be deleted.