#2 OP, could just be really unlucky? Its only supposed to be rerolled once and the second value is kept, at least per 5e rules for table top. Without the reroll appearing in the log you can't actually know without seeing it happen repeatedly. Normally you would expect a 4 or less on 2d6 about 1 time in 6 without the reroll.
I haven't had the followup attack trigger either. It shouldn't require the -5 to hit +10 damage mode on to activate, but I haven't check to see if that makes a difference or not
