Almost giving up on the newly purchased 712 CB, I went to a club fitter for an opinion. I brought the 712 CB together with the irons I previously used, the FG 62. I told the fitter I was striking the ball well with the FG 62 but not with 712 CB.
After checking, the fitter found out that the 712 CB was 2 degree upright. This explains why I was skulling and at times pulling the ball left. Got it fixed. Lo and behold. I found the sweet spot again and again. Sharing this to team titleist.
Not being able to find sweet spot could be due to many reasons. Getting the lie angle fixed is eliminating one. Cheers !