Who told you roasted veggies would last past day two? They lie. Broccoli especially turns into a wet sponge by Wednesday no matter what you do. The trick is to roast them plain, keep them in a separate jar, and only add sauce right before you eat. Same goes for the sweet potatoes, they just soak up whatever moisture is nearby and get gummy. So yeah, your mush was doomed from the start, not your fault.