@cory have you one dark background element or two? @fayewatson seems to assume two but you answered referring to one. Therein may lie the solution. Have you tried combining all the element on the left into a transparent group than doing the same for all the elements on the right? That would be a good starting point if that’s not already the case.
If that doesn’t work, and I had a very similar problem myself recently, then check the min/max sizes are identical to other elements, then check in the responsive editor to ensure all attributes are the same there. If all else fails, and it did for me, try adding two new fields, see if they behave correctly and if ‘yes’ then delete the misbehaving fields. I’ve found that final step often works in bubble.