I have to use \cleartooddpage to get the desired behavior. As I integrate that command I get 4 error messages related to the line of the first begin{figure} directly after the command: Missing number, treated as zero. \begin; You can't use `\spacefactor' in vertical mode. \begin and twice: Missing $ inserted. \begin. (caption contains math mode terms) without any of the newly defined commands no error occurs.

It seems removing the h forces a better behavior but the page before the first figure the spaces between the paragraphs are stretched to several centimeters.

Thanks for the hits. I tried to integrate that. The principle is doing, what was asked, but the pictures are flushed to the end of the chapter. Any further ideas?

And see the other topic tex.stackexchange.com/q/562607/206959 for the details. This seems to be an issue Win only bug.

Something is still strange:in a reactions-environment another similar \SIrange- Command :A + B &->[ "\SIrange[range-units=single,range-phrase={~--~}]{20}{30}{\c‌​elsius}" ] C + D causes Errors:"Package siunitx Error: Unknown option 'range\chemformula_single_bond:(siunitx) units\chemformula_double_bond: single'. \end" and "Package siunitx Error: Unknown option 'range\chemformula_single_bond:". As I puzzled out, the {...} in the range-phrase option is the root of the evil. range-phrase=\ --\ is without errors. Outside the environment both versions are o.k.

Thanks as well for improving the question.

Thanks for the detailed explanation. And the hint to the solution.

As you see, I changed the info. The issue is the same in all use-cases. But what is the difference between option range-units and range-phrase ?