Hi @arese8c. I'm still getting the hang of chromecast but I just checked and once you cast a playlist, chromecast streams direct from spotify's servers (you can check by turning off your mobile after casting). This makes casting equivalent to the way connect works so I would expect the same limitations to apply' As I only bought my chromecast a few weeks ago, I can't comment on whether this only started recently.
Other issues common to chromecast and connect are daily mix and radio not adding tracks after the initial selection.
Re: Chromecast audio - playlist always returns to beginning