Whats with this joint compound?having issues with cracks.?

i have done a lot of home remodeling.when i sheet rock i have always used the sheetrock brand compound with the green cover.never had a problem.so i just remodeled my brothers master bathroom and since i heard the sheetrock brand with the blue cover was better i used it.i have cracks at the joints every wheres now.i did the usual using mesh tape and made sure all my joints over door casing's and windows were where they should be.yet the cracks come back.my brothers house does have a full concrete basement and before i removed and replaced all the sheetrock with new sheetrock the bathroom didn't even have a crack in it.i know for a fact i screwed all the sheets in right.so whats with this light weight compound?