The question is: Is the loss of the significant p value because it was driven by 2 data points from group 2 or there is no enough power for the second analysis?. Can I conclude that there result is not significant as it was driven by 2 points for the first case(group 1 and 2 first plot)? your help is very appreciated.
Once you have performed multiple tests, you should really correct for them. Under the standard corrections, all your tests will be non-significant. Which is not surprising, because you have very little data, and the correlation is indeed quite weak.
Then again, this is a bit of a purist position. You would not be the first to report an uncorrected p-value for the overall analysis, and p-values corrected for only two tests on two subgroups. (Or here, an uncorrected p-value for a single subgroup.)
Your results on the total dataset are driven by the two data points. It makes no sense to discuss "post-hoc power" after you have observed the data (Hoenig & Heisey, 2001)).
Finally, note that The Difference Between “Significant” and “Not Significant” is not Itself Statistically Significant (Gelman & Stern, 2006).