This is because Server Perks supports up to 200 Millions of damage, when you earn more than that, it starts making problems. To fix that you will have to edit ServerPerksP.u.
You can fix that by doing this:
Find the function static function int GetPerkProgressInt( ClientPerkRepLink StatOther, out int FinalInt, byte CurLevel, byte ReqNum )
In this function you will see a default formula that will calculate how much damage you will need for the final level. In your case it is 251.
default:
FinalInt = X + GetDoubleScaling(CurLevel, Y); //Where X and Y are some numbers
You will have to calculate the max damage to be 200 Millions.
GetDoubleScaling = Your max level - 6 = 251 - 6 = 245
Therefore:
FinalInt = X + 245 * 245 * Y
You have to play with these X and Y numbers to get it right. Use the calculator to do that.