KtLint check doesn't work locally anymore - it works tho in my docker image build

Question

For no reason I am able to understand my gradle ktlintCheck command does not yield any issues anymore and :ktlintFormat is not fixing anything. As soon as I push my changes and my CI pipelines starts to build my Docker Image build process ktlint does work again.

So to be clear - I have issues and ktlintCheck does not find them.

The only real delta I did was updating Kotlin to 1.4.10 and also ktlint to 9.4.0. I think it has something to do with that but can't figure out what.

Locally

7:57:41 PM: Executing tasks 'clean ktlintCheck'...

> Task :clean
> Task :ktlintMainSourceSetCheck
> Task :ktlintTestSourceSetCheck
> Task :ktlintKotlinScriptCheck
> Task :ktlintCheck

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.6.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 1s
4 actionable tasks: 4 executed
7:57:42 PM: Tasks execution finished 'clean ktlintCheck'.

CI Pipeline

Step #0 - "Build": Starting a Gradle Daemon (subsequent builds will be faster)
Step #0 - "Build": > Task :clean UP-TO-DATE
Step #0 - "Build": > Task :compileKotlin
Step #0 - "Build": > Task :compileJava NO-SOURCE
Step #0 - "Build": > Task :processResources
Step #0 - "Build": > Task :classes
Step #0 - "Build": > Task :bootJar
Step #0 - "Build": > Task :inspectClassesForKotlinIC
Step #0 - "Build": > Task :jar SKIPPED
Step #0 - "Build": > Task :assemble
Step #0 - "Build": > Task :ktlintKotlinScriptCheck
Step #0 - "Build": > Task :ktlintMainSourceSetCheck
Step #0 - "Build": 
Step #0 - "Build": > Task :ktlintTestSourceSetCheck
Step #0 - "Build": [90m/builder/src/test/kotlin/com/mygame/backend/extension/[0mResolverExtensionTest.kt[90m:[0m39[90m:33:[0m Argument should be on a separate line (unless all arguments can fit a single line)
Step #0 - "Build": [90m/builder/src/test/kotlin/com/mygame/backend/extension/[0mResolverExtensionTest.kt[90m:[0m40[90m:57:[0m Argument should be on a separate line (unless all arguments can fit a single line)
Step #0 - "Build": [91m"plain" report written to /builder/build/reports/ktlint/ktlintTestSourceSetCheck/ktlintTestSourceSetCheck.txt[0m[91m
Step #0 - "Build": [0m
Step #0 - "Build": > Task :ktlintTestSourceSetCheck FAILED
Step #0 - "Build": [91m
Step #0 - "Build": [0m[91mFAILURE: [0m[91mBuild failed with an exception.[0m[91m
Step #0 - "Build": [0m[91m
Step #0 - "Build": [0m[91m* What went wrong:[0m[91m
Step #0 - "Build": [0m[91mExecution failed for task ':ktlintTestSourceSetCheck'.[0m[91m
Step #0 - "Build": [0m[91m> [0m[91mA failure occurred while executing org.jlleitschuh.gradle.ktlint.KtLintWorkAction[0m[91m

Excerpt from build.gradle.kts

buildscript {
    repositories {
        maven("https://plugins.gradle.org/m2/")
    }
    dependencies {
        classpath("org.jlleitschuh.gradle:ktlint-gradle:9.3.0")
        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.3.3.RELEASE")
    }
}
plugins {
    id("java")
    id("eclipse")
    id("idea")
    id("org.jlleitschuh.gradle.ktlint") version "9.4.0"
    id("org.springframework.boot") version "2.3.3.RELEASE"
    id("io.spring.dependency-management") version "1.0.10.RELEASE"
    id("com.adarshr.test-logger") version "2.1.0"
    kotlin("jvm") version "1.4.10"
    kotlin("plugin.spring") version "1.4.10"
}

Dockerfile:

FROM gradle:6.6.1-jdk14 as builder
USER root
WORKDIR /builder
ADD . /builder
RUN gradle clean build

FROM openjdk:14-slim
WORKDIR /app
EXPOSE 8082
COPY --from=builder /builder/build/libs/alemanni-backend.jar app.jar
CMD ["java", "-jar", "app.jar"]

Any idea why it does not work?

EDIT: Maybe related to this issue: https://github.com/JLLeitschuh/ktlint-gradle/issues/399