It would be out of spec on most mods although as I recently learned, that spec may be meaningless in many cases. The dna 40 for example will fire any coil at any ohms, including for TC. Tested with TC at up to 4.2Ω with Ni200, and 3.5Ω with Titanium. It just soft limits the power if necessary, and the 1.0Ω limit for TC appears to be nothing more than a suggestion, designed to ensure the coil can be heated with full power, out of the soft-limit area.
The same should apply to the Dicodes and in their App Note For Temp Controlled vaping they actually give a suggested TC range (for Resistherm) of 0.5Ω - 1.5Ω. So it should fire any ohms with TC - any supported by the mod in general that is.
So I'm not saying the 1.0Ω isn't a problem, but it certainly shouldn't be on the Dicodes. Although rather than the 1.0Ω specifically, I'd say the problem is more likely to lie - as Arthur indicated - in the number of wraps / size of the coil making it more likely to be unstable.
As he is planning, a good place to start would be with a Ni200 build along the lines of that done in the video, then working from there. Build something that's known to work elsewhere, and then see how much it can be changed and in what ways. That might isolate the area of the problem.
If he finds that even with a basic Ni200 build he has the same issue, then he might need to write his particularly In'ax off as unstable for TC.
