Hi Sreejith,

>>>>Does anyone face the same problem.
Have not had such problem with AC 2020 on my side.
What kind of blocks are you using? Looks like you always have problem with them...

BTW, have you installed 2020.1 Update which was released recently?
https://up.autodesk.com/2020/ACDMAC/AutoCAD_and_AutoCAD_LT_For_Mac_2020.1_Update_Readme_ENU.htm
Looks like it should resolve some problems with Blocks palette, not sure about your problems with blocks properties.