2:183. O ye who believe! Fasting is prescribed to you as it was prescribed to those before you, that ye may (learn) self-restraint,-
As this was the case, were they still 'fasting' in some way?
Were they doing it correctly?
187. Permitted to you, on the night of the fasts, is the approach to your wives. They are your garments and ye are their garments. Allah knoweth what ye used to do secretly among yourselves; but He turned to you and forgave you; so now associate with them, and seek what ...
This suggests that they were not and the Quran came to correct what they had been doing, just like it corrected a lot of what others believed and did.
My 2cents worth.