Here's a link to the character sheet in question:

https://www.dndbeyond.com/profile/DanielStier/characters/25768029

Currently the damage bonus on all of his melee weapons is showing up as +11 or +12 depending upon whether they are magical items or not.  He's a level 8 rogue/level 2 paladin. His Dex bonus is +3 and he has the dueling fighting style.  His total damage bonus on a +1 weapon should be +6 with his fighting style bonus and dex bonus.  I have tried removing all of the homebrew items from his inventory, (Corpse slayer, dagger and Crusader's Silver) and unattuning and reattuning all of his items.  With a single regular rapier equipped and nothing else his bonus still reads as +11.  The only thing I can think of is that the dueling fighting style is being applied multiple times for some reason. I recreated the character in another slot, added all of the same homebrew items, and that character's damage bonuses read out correctly. 
Here's a link to that character if you need a comparison. 
https://www.dndbeyond.com/profile/ReallyGreatPizza/characters/34652528

Thanks in advance for the help!

You are probably right that the Duelling Fighting Style is being applied multiple times. The fix for this is to go into the builder and change the Fighting Style to the top "- Choose an Option -" setting and keep doing it until it stays that way. Then choose Duelling again. That should fix it.

The fix did indeed work. Thanks for the help!