Not sure if this is an intentional change, however the burner miners setup in a 2x2 don't seem to work forever.
Instead one of them stops outputting then the others eventually run out of fuel.
(no mods other than this one)

In the image below, the one on the bottom left is out of fuel (was flashing out of fuel), and the one on the bottom right wasn't outputting as seen by the selection.
Note that the destination burner minor has no fuel in it.

I think the issue is that the invisible beacon I'm using to speed up the burner machines is getting in the way. I'll see if I can fix it.

I think I've fixed it, patch releasing momentarily

nevermind, that didn't fix it. Hold on

it should properly be fixed now. The patch should be out

Awesome! ty for the super fast response!
And I think I can see that beacon as it's highlighting the small tile instead of the full burner miner.

I had to pickup and put down the burners but that worked they are no longer blocked, but now they don't have a productivity bonus. Hmmm
Still testing, I'll reply if I notice it come back.

I changed the productivity to only apply on the fuel's speed value, not its acceleration, because I felt it was too powerful. You no longer get any productivity by using coal anymore, and you have to use higher-tier fuels, such as coal coke or solid fuel, to get any productivity bonus.