Error/Warning Highlighting stuck for scala 3.1 / bsp / mill project

I got this issue where the "Error/Warning Highlighting" background task is always running on my scala 3 / bsp / mill project. It stops me from doing anything really , the IDE is unusable because a lot of tasks can't run (like the compiler).

Any ideas how can I debug this?

I got this project here, https://github.com/kostaskougios/myconsole

I am on these (using nightly builds of the IDE):

IntelliJ IDEA 2021.3.1 (Community Edition)
Build #IC-213.6461.79, built on December 28, 2021
Runtime version: 11.0.13+7-b1751.21 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Linux 5.13.0-22-generic
GC: ParNew, ConcurrentMarkSweep
Memory: 1863M
Cores: 16
Registry:
scala.erase.compiler.process.jdk.once=false

Non-Bundled Plugins:
idea.plugin.protoeditor (213.6461.28)
org.jetbrains.kotlin (213-1.6.10-release-923-IJ5744.223)
org.intellij.scala (2021.3.516)

Kotlin: 213-1.6.10-release-923-IJ5744.223
Current Desktop: ubuntu:GNOME