My analysis of your demo video is that you have your understanding of your fixture's DMX channels all wrong. I fell into the same hole when I first started.
You will notice that when you lowered DMX 1 by a small amount, it triggered Blue to literally cut out, and nothing happens thereafter between values 90-10 or thereabouts. At about 10% or less, Red cuts out.
Next nothing happens when DMX 2 is lowered, until at about value 0 and Green cuts out, even though DMX 3 is still at 100%. This seems to imply that Green is not DMX 3 or if it is, because DMX 1 is at 0, DMX 3 will not react.
Next, when DMX 3 is lowered, Blue immediately flashes on to 100%, then slowly fades down following DMX 3 value. This may imply that Blue has a DMX address of 3, but see below.
It is very rare that a fixture would have only 1 DMX channel these days, unless you are using fluros or incandecents in which case, you would need a dimmer.
So in the case of your latest illustration, using LEDs, I think that fixture has at least 4 DMX channels, maybe 5 (Morgan's seem to have 6; mine has 4), where -
DMX 1 is Intensity (and in my case, strobe/flash rates as well depending on the value)
DMX 2 is Red
DMX 3 is Green
DMX 4 is Blue
The DMX Address to set on the fixture is 1. It is implicit in the 'language of DMX control' that DMX 2, 3 and 4 are tied to this fixture when DMX 1 is set. This means, the next fixture down the chain will have a starting address 5 (and if the same type of fixture, occupy addresses 6, 7, and 8 as well). The 3rd fixture will have starting address 9, etc. Doing it any other way will result in unexpected behaviour as shown in your video. This assumes your fixture has 9 dip switches numbered 1-9. Mine has 10 where no.10 is DMX control when ON. For some other fixtures, it may be numbered 0 for DMX Control.
So try this -
1. DMX 1 value = 10%
DMX 3 value = 100%
Only Green should light up if your fixture follows the normal order of RGB.
2. DMX 3 = 0
DMX 2 = 100
and Red should light up.
3. DMX 2 = 0
DMX 4 = 100
and Blue should light up.
4. Leave Blue on at 100.
Now vary DMX 1 from 10% upwards slowly and see if the behaviour of Blue changes - gets more intense? flashes? Note the value(s) at which the intensity is steady and bright. For your installation, if you do not want flashes, you would set DMX 1 to this steady state for EVERY color/fixture of this type.
5. You may try DMX 5, 6, 7, etc to check if this fixture reacts to these other channels. If no reaction, then you have 4-channel fixture. If it reacts to channels 5, etc, then the next fixture's address is the channel number after that last reaction.
Similarly, if you have different type of fixtures in an installation, you need to discover the personality of those other fixtures in order to map your channel assignments properly for the whole install.