Yes, that might be the case with this object. My intention was to provide RGB and NB (Ha) datasets for you in order to evaluate if your 'Ha as L' workflow works (well) if both datasets originate from a modded DSLR (and therefore RGB data contains a decent amount of Ha). Of course, maybe this object is not suited very well, but I hoped at least well enough.
OK, that seems to be yet another workflow as that one you described here before. And it might be that it is easier to get a an expected (or more convenient) colouring with douband data in this case, depending on the object (I think Mike wrote this already).
I really like this image, Freddy! And of course your unmodded DSLR is able to capture red colour, but this is not a proof for that your 'Ha as L' workflow will work fine with RGB data from this camera, beeing combined with Ha data from your mono camera. There is for sure a mismatch which might lead to the recurring problems with colouring that you encounter (please have a look at Mike's last post as well).
And I'm not sure that this approach works fine even having both datasets from modded cameras (or OSC astro cams). If you have a look at my both M1 images you will notice that the visual spectum M1 seems to be somewhat 'smaller' then the duoband version. And of course, this is because it is possible to get 'deeper' images having the duoband filter eliminating the LP. So there are areas visible in the duoband version that aren't visible in the RGB version. But what happens now if you try to colourise these areas in the douband image and there is no corresponding colour data within your RBG dataset? And I'm afraid, that will be the case most times ... ?! I dunno, Freddy ...
Best regards, Dietmar.