Lulin, the green comet has a red tail?

Has the green comet a red tail?
Here is a calibrated LRGB composite of 90 photos (120s each) taken this morning, 22 February, between midnight and 3 o'clock AM. After registration on the comet core, I stacked them using the 'minimum' algorithm of CCDStack. This gets rid of the star trails and isolates the comet. Then I added a single 120s luminance shot to show the star field at 3h06 AM.
The comet is green as advertised but what a surprise to see a red tail!. Fact or artefact?
NB: a red tail for a Chinese discovery seems in order!