Alright, I just got off of support with TurboTax and found a solution, so I'll put it here for reference if it is helpful for the original poster:
My rental income is from renting a room that is part of my home property. So when I put in all of the expenses that I want to deduct against my rental income, I've always manually calculated the portion of total housing expenses that I want to apply against that rental income. But since there are some expenses that are strictly for the rental unit, and some that are shared, it's a mixed calculation.
Now after I had entered all of these expenses, upon final review, I was prompted to enter what percentage of my home my rental unit was. I put in 33%, but what this did was revise the expenses that I had already corrected for this portion to a third: so in many cases expenses were now showing as a 1/3 of what they should be. There is no way to fix this, so if you manually calculate your expenses, watch out! TurboTax instructed me to delete the whole Schedule E worksheet and start again.
Then when prompted for that percentage on final review, BE SURE TO TYPE IN 100% if you don't want your expenses all automatically adjusted by that percent.
