Undefined Friend Request? What Means?

Hi ... some my students trying to connect with each other all in our club and one student tries to connect to another and usually all is good ... however one user when he click friend ... a red bar appears at top saying "undefined"

What this mean? 

Thx!

Maybe the requester changed their username after sending the request

@Martin_Stahl ... you know that may be it ... i will have them unfriend or remove request and try again ... nice thinking ill let know in few days if such worked ... Thank you

Reload your page or change browser

@turtlekid2022 per your stats being so low i think you should keep to study chess and revert back in three years to chime in on big boy talk per tech and anthing else really ... i have students of pre K that have more respect and knowledge than you ~