[Problem with Accel and Jerk settings for Marlin]

Using Cura 2.5 and 2.6, my printer is set up as a custom printer using GCode flavor "RepRap (Marlin/Sprinter)".

In Cura I have these as my settings:

Print Accel: 800

Travel Accel: 850

Print Jerk: 10

Travel Jerk: 15

According to documentation (http://marlinfw.org/docs/gcode/M204.html and http://marlinfw.org/docs/gcode/M205.html) this should produce the following Gcode:

M204 P800 T850

M205 X10 Y10

What I find in the GCode instead is:

M204 S850

M205 X15

M204 S800

M205 X10

Using Cura I set both accelerations to 800 and both Jerk to 10.  Then I pulled the settings from the firmware using M503 and this is what I got:

Recv: echo:Acceleration (units/s2): P R T

Recv: echo:  M204 P800.00 R1000.00 T800.00

Recv: echo:Advanced: S T B X Z E

Recv: echo:  M205 S0.00 T0.00 B20000 X10.00 Y20.00 Z2.70 E5.00

So clearly Cura is not setting Y jerk and not interpreting the M205 reading correctly.  How could I fix this?