No locked image for :UI.Item.icon

UI menu runs really smooth at times but then I get spammed with this error in console
No locked image for :UI.Item.icon 1-26
UI menu then gets very laggy and hard to work with.

Just to expand on this a little, the lags occur when the errors are giving random numbers at the end, I get the error as well where the numbers go consecutively but everything seems fine then.