Your base strength is 8, so a -1 modifier, and you then get your +7 for the difference (+6 for 23 Strength, and +1 to compensate for the -1).
That does not seem anywhere close to correct.
Your base STR is not 8, your base STR is whatever you come out of CC with. I have no idea where this 'compensation' +1 is supposed to come from. There would be no drawbacks to having a negative attribute score if it was cancelled out by compensatory additional point or points.
The +6 in the image comes from a STR of 23 or 22 really as it only increases on the even numbers. 10 is +0; 12 +1; 14 +2; etc.
According to the image the actual saving throw should be 15 not 16. 12 + 6 + 6 + 1 + 1 + 1 = 15.
I would guess that the -1 comes from an equipped item or an effect (curse maybe?). Do any other party members have it? Are there any small icons attached to the characters thumbnail portrait? Have you looked at the character's character sheet?