Shouldn't wash sales not be an issue if you use FIFO when selling shares? Fidelity gave me fits with their 1099 reporting a few years ago with regard to a wash sale I don't think really happened.
I sold a bunch of shares back in September of 2018, about 2 weeks before and after an automatic dividend reinvestment. One purchase was at a slightly higher NAV, the other lower. Fidelity made no mention of any wash sale. I use FIFO for cost basis, so the shares I actually "sold" were those I bought in 2006 and 2007. I made about $40 on the sale.
Fast forward to January of 2020. I sell some more shares. Using FIFO again, I am selling shares from 2007 and 2008 and made about $1,500 on the sale. But Fidelity, for some reason, has flagged those 2 dividend reinvestments surrounding the September, 2018 sale as wash sales. They, for some reason, included them in the cost basis of the January of 2020 sale. The disallowed wash sale loss comes to 17 cents. It has no real affect on my taxes, of course, but it has turned my spreadsheet into a small mess because there is a 10-year gap between the shares I actually sold in 2020.
I asked Fidelity why they did this, after taking a while to actually determine that they had done this (there was an error on one of the dates in their 1099 form I had to get passed). That's when they told me about wash sales even though I told them I used FIFO. And there was nothing flagged on the 2018 sale.
I still don't know how a wash sale developed from either sale.