Looking out at my combustion farm, every looks normal.
But as I moved further in, I noticed something weird.
There isn’t a water source above, but it still looks like this. And if the lava gets wet and changes to Igneous, does that mean the chiseled gleam blocks are gone?
Yes, the gleam blocks are gone.
Not sure where your fluid leak came from but it can also be resin or petrolim, it doesn’t have to be water.
I do have resin flowing at my shop, but it’s about 2 plots away. I honestly am confused…
Looking at your screenshot, it looks like the stone forms a circle. I would find the center of that circle, then dig up, see what you find 
lava doesnt solidify by resin or petrolim! no night!
once accidentally had lava interact with a petrolim fountain and bam n0th1ng
They interact when the lava is in a chiseled block
I can confirm resin solidifying lava - had an accident once when building farm and I ran out of lava in my liquid smart stack, placing resin then instead, and it solidified lava.
You have tilled soil in your ceiling, does this mean you have plants above that require a water source? Perhaps when you were chiselling the Refined Stone to put the water in, you accidentally chiselled a gap in it that made the water spill through?
And I can also confirm resin/petrol react with lava the same way water does 
I do have tilled soil in my ceiling with wheat growing up there, but since it grows good with mud or water, I have mud up there, so no water coming through.
I can’t tell from the picture, but the area looks like it may be larger than a single water leak would have caused. Maybe try and find the center and take a look at the overall pattern.
