UI Theme Designer Error

Hi,

        When rebuilding the client theme, found this error:

Uncaught Compilation Error "variable @sapContent_ContrastTextTreshold is undefined" in line 1 column 34 called by object "Base.baseLib.zviridor_theme.base.sapButton_TextColor" of type "sap.theming.less.Parameter" in "fExternalAssignmentParser"

Extract:

Line 1:x{x:contrast(#f7f7f7, #333, #fff, @sapContent_ContrastTextTreshold)}

Please find the attachment