Hi,
The Lineweight is not changing because it's not a line, but its a Block reference. If you want to change the line weight of the particular line you need to go into block editor and then change the lineweight. To do that select the block right click and then select "block editor" now inside the block editor you can choose the line and then change it's line weight. If you are still not able to see the lineweight making any effect, type in the command "LWDISPLAY" and type in "ON".
--------------------------------------------------------------------------------------------------------------------------
ವಿನೋದ್ ಕೆ ಎಲ್( System Design Engineer)

Likes is much appreciated if the information I have shared is helpful to you and/or others.
Please mark "Accept as Solution" if my reply resolves the issue or answers your question, to help others in the community.
--------------------------------------------------------------------------------------------------------------------------