Channel integration is ruined when adding new channels

I am imaging M57 with different filters, both narrowband and wideband.

When I integrate my Ha 3nm channel only, I get a good result, with good dynamic range showing gradients and details (see attached image).

But when I add to the project the other two channels, which has a significantly stronger signal (Green and Oiii-7nm) - I get a very bad integration of the original Ha data (integrated separately of course) - it is "flat" with almost no gradients and details

(see attached image).

My understanding was that I should get an identical outcome of this channel, but it seems to me that the Ha processing is somehow influenced by the other channels (normalization perhaps?) that were added. I cannot figure out what I am doing wrong that is causing that and what I should do in order to change that. Your assistance is appreciated.

Thanks, 

Assaf

(P.S. I am working with version 1.083 beta)