I've experienced this with the last few tanks I've fishless cycled.
Two things stand out to me. 1) I also used a bacteria supplement, though in my case seachem stability, and remember thinking that the constant 0 nitrites was odd
2) I also used higher temps for them > 80°
I know the species of bacteria that convert nitrite to ammonia do not reproduce as quickly as the others but possible they consume at a faster rate?
They don't all develop at the same time. Water temp can influence growth rate.
How long did it take for you tank to cycle with Stability?
Remind me again, what brand/type of media are you cycling?
I have Bio Max in the filters, I'm cycling Fluval ceramic rings as it's the only thing I could find locally in decent amounts. For whatever reason Fluval doesn't sell big boxes of Bio Max or it's just my local stores don't carry it.
Since my tanks have decided to chill out, I can focus on what is going on with this cycle. Yesterday I bought a bottle of Aqua Safe Plus. I added some this morning to the bucket. I just tested it and got weird results. The picture is horrible and out of focus, but I don't feel like testing again for the sake of a picture.
Knowing that API nitrate tests can be unpredictable, this may be nothing or something. The label on the Aqua Safe Plus doesn't say anything about removing nitrates. The nitrite weirdness happened before I added the water conditioner so that still remains a mystery.
If I had trace amounts of chlorine in my water, would that kill off everything to the point of no return, or would the bb grow back once the chlorine was removed? I looked all over the place for a chlorine test yesterday and couldn't find one. I don't know why chlorine is a issue in my brain right now, but something still isn't right and I want to know what messed up my tanks.