In one of the groups, I defined 8 samples but it shows only 6 of them. Other 2 I can see the on heatMap but coloured differently (matched with another group). I can see this in edger and deseq2 results.
This is not enough information to reproduce or understand your issue. If you were using the webserver, please provide jobID and a bit more background on what you were trying to achieve.
In one of the groups, I defined 8 samples but it shows only 6 of them. Other 2 I can see the on heatMap but coloured differently (matched with another group). I can see this in edger and deseq2 results.