Bleached ends turned denim blue without toner?

I had this happen with blue bleach (DIY effort though) my ends were a mixture of yellow, green and blue. 
I suspect the bleach might have been left on a little bit too long so the blue toner in it that's meant to counteract the brassiness has had more of an effect than was intended.

Go back to the salon, speak to the manager or head colourist type person and get THEM to fix it, since its their error.

FINALLY. I've been all over the internet searching for somebody with the same experience. Unfortunately, the  Salon I went to has their clients sign a waiver for big color jobs, and discusses the potential issues of bleaching beforehand. Blue was not discussed, but because of the waiver I can't get her to fix it without going out of pocket again.

I ran a light bleaching over it, and it brightened, but more blue appeared. I used 2 different color removers (color oops and Jheri Redding Color fix) and did a bleach wash. Then I found a warm blonde box dye. That actually got rid of a lot of blue. I followed it with Blonde Brilliance in Misty Rose. Now almost all of the blue is invisible, but I have Silver, Rose gold, and Bronzeish hair!!

1st, 2nd, and 3rd place in the "What the hell is happening to your head" competition!

It is definitely better now though. I'm gonna go back at it with some strawberry blonde again in a few days and see what happens.

That is a 'sledgehammer to crack a nut' approach.
A simple clarifying shampoo should have been your first stop, then you could have toned out any remaining blue.
Chemical damage is cumulative, permanent and takes weeks to fully show, so I wouldn't recommend you process your hair again after all it has been through in the last week.

was your brown hair virgin hair or dyed? Just thinking if it was a dyed brown that may be why the bluey colour appeared when the hairdresser lightened it, as some dark colours can be that colour when stripped. But yes, I wouldn't touch any more bleach, permanent dyes or demi dyes for a while like Wicked Pixie says

My first thought was, is this virgin hair or previously dyed hair?

Previously dyed hair. I've never had this happen before, and was able to get my hair to white from many layers of black dye. This time things went sour.

I tried a clarifying shampoo, and so many other methods! 🙁

I've used colorfix once, and am still letting my hair rest and deep conditioning/coconut oil treating until Sunday, where I'll try it again.

Sunday is too soon to try again--you won't know how much damage the processing has caused for several weeks just yet, and you risk your hair becoming so fragile it snaps off.

If you want to add a bit of warmth back in to your hair, try using a true semi like Adore and diluting it down with conditioner to tone through your hair.