css - node.js less removes background property when there are two using variables -

i have problem less:

@frames_color: #faeacd; @menu_color_hex: #faeacd; @menu_color_rgba: rgba(250, 234 ,205 , 255); 

with less:

.topmenu {     {          background-color: @menu_color_hex;         background-color: @menu_color_rgba;     } }        

results in css:

#user_field .topmenu {   background-color: #faeacd;  } 

and

.topmenu {     {          background-color: green;         background-color: @menu_color_hex;         background-color: red;         background-color: @menu_color_rgba;         background-color: blue;     }  } 

results in:

#user_field .topmenu {   background-color: green;   background-color: red;   background-color: #faeacd; /* value of menu_color_hex used instead of menu_color_rgba? */   background-color: blue; } 

i'm clueless atm. why removes 1 background-color property? bug or intended behaviour?

in @menu_color_rgba: rgba(250, 234 ,205 , 255), "255" not valid alpha value (it ranges 0–1).

if don't need alpha value, working rgb instead has more browser support (rgba not supported in ie8 example).