Maven project as branch cloned from gitlab is not visible on IntelliJ

I am sure I must be missing something but here is my scenario. 

I have a Java based project in gitlab, which has several branches on it. I've cloned the project from IntelliJ and able to see list of all branches from Project->right click ->git->branches. I could able to checkout every branch as new branch and the contents of all the branches are visible in IntelliJ expect one branch(refer this as mvnbranch). This specific branch is maven project(all other branches are normal Java projects) and all that I see, when I switch to mvnbranch is empty. 

I've cross checked my repo contents by cloning through standalone git(using mac terminal git) and I could see all the branches and contents including the above one.

Question is, why I am unable to see any content on my maven based branch only? attached screenshots for further review.