error style.css.map (not found) ??

i get this error (with developer tools plugin in chrome) :

GET http://domainname/wp-content/plugins/dw-question-answer/inc/templates/default/assets/css/style.css.map 404 (Not Found)

also found this file style.css.map is missing
(ofcourse try create a blank file with same title and error stop.)

any info about ?

https://ww.wp.xz.cn/plugins/dw-question-answer/