I am experiencing the same issue. My balance sheet account on a cash basis for last year is about $17k overstated but when I drill down into the account, cash basis for the same time period, it is the balance it should be. Accrual detail matches the accrual balance, but that doesn't help me when I need the cash basis version of these reports. I am unable to tie the balance sheet report total to any detail.

My difference from your original post is that I don't have any credit memos but I do have journal entries that are adjusting the balance.