local.days not displaying as expected when sundayFirst is set to true

[gemrao]

When local.days is set when sundayFirst=true . The calendar days are not displayed as expected

let local = { format: "DD-MM-YYYY HH:mm", sundayFirst: true, days:[ 'Mon','Tue','Wed','Thur','Fri','Sat','Sun' ] }

Actual

Expected

Please let me know how this can be resolved.