[pauke]

I believe it's a similar thing. Semi-educated guess based on historical facts: Because of various (not least religious) reasons, Czech-speaking intelligentsia pretty much ceased to exist mid-17th century (fact, replaced by German/Latin) and only actual serfs spoke Czech, work and robota became defacto synonym (speculation). And when it became fashionable and cool to speak Czech 100-200 years later for the city-dwellers (fact), they probably felt the need to differentiate whatever they were doing as a job from the definitely uncool farmers of the countryside (speculation).

[int_19h]

The evolution is the other way around - the original meaning of that root in proto-Slavic was obligatory work, and that one in turn is a derivative of a PIE word with the same meaning.

https://en.wiktionary.org/wiki/Reconstruction:Proto-Slavic/o...

https://en.wiktionary.org/wiki/Reconstruction:Proto-Slavic/o...

https://en.wiktionary.org/wiki/Reconstruction:Proto-Indo-Eur...