I have this same exact issue in Cura 3.1.0. No matter what values I put into all the extruder temp fields and yes I changed all of them, it still outputs 210 into Gcode, see below ( and yes bed was set at zero on purpose) It changes to the correct temp much later in the gcode. I do not understand what is going on
M104 S210 ; set extruder temp
M140 S0.0 ; set bed temp
M190 S0.0 ; wait for bed temp
M109 S210 ; wait for extruder temp