The teacher ID may be incorrect or missing in Edval. The teacher ID needs to match or be entered into Edval. 

You should find that In Edval in Teachers > Teacher Data> Sentral ID. If you enter the number there, then re-publish from Edval, it should recognise them correctly.  

To find the issues go to Timetables Setup > Teacher Mappings

If any problems are detected, they will be noted here.