Any way to prevent error-squigglies on the indent guides?

[Hubro]

When LSP servers produce errors for blocks of code like this:

The indent guides also get the error underline, which looks super messy and buggy.

Is there any way to prevent this?

[lukas-reineke]

This looks like a problem with your color scheme.
Can you post the output of :highlight IndentBlanklineChar?

[Hubro]

:highlight IndentBlanklineChar
IndentBlanklineChar xxx guifg=#313244

[lukas-reineke]

Yeah this is the problem. It is also mentioned in the documentation.

When defining the highlight group, it is important to set nocombine as a
gui option. This is to make sure the character does not inherit gui options
from the underlying text, like italic or bold.

You need gui=nocombine on that highlight group.
If this is your own color scheme, just add it. If not, make a PR or issue in that repo to fix it.