Exception shown in Tomcat startup

Hi there- is this cause for concern? The theme seems to be working ok:

java.lang.Exception: Mixin Definition: rubric not found
at com.vaadin.sass.internal.visitor.MixinNodeHandler.replaceMixins(MixinNodeHandler.java:40)
at com.vaadin.sass.internal.visitor.MixinNodeHandler.traverse(MixinNodeHandler.java:33)
at com.vaadin.sass.internal.tree.MixinNode.traverse(MixinNode.java:104)

Have you definined a @mixin in your theme called ‘rubric’?

Thank you John. I have this is my scss:

@import “…/reindeer/reindeer.scss”;

.rubric {
@include reindeer;

and this in styles.scss (as recommended by Jouni Koivuviita):

@import “rubric.scss”;
@include rubric;