Indent lost in big json file

[Lun4m]

I have a big json file, with 3 spaces indent. At the start it looks fine:

After some lines however, I get this:

It seems to depend on the fact I have vim.opt.shfitwidth = 2.
Is it a bug or expected behavior?

Edit:
I'm also using mini.indentscope to highlight the indentation level at the cursor position, and it manages to detect the correct level.

[lukas-reineke]

This is expected behavior.
IBL uses both your settings, like shfitwidth, as well as the surrounding code, to determine indentations.
But looking at the surrounding code from the beginning of the file would be very slow, so by default it only looks at 30 lines above the first displayed line.
So if the start of the indentation is further up than that, it uses shiftwidth instead.

You can change how big this buffer is with :help ibl.config.viewport_buffer.min, but the correct solution is to just set shiftwidth.

[Lun4m]

Thanks for the explanation!