SpringBoot SpringDataWebSupport throws MethodArgumentConversionNotSupportedException in Spring Boot 2.3.1

The following code works perfectly on Spring Boot 2.3.0, but throws org.springframework.web.method.annotation.MethodArgumentConversionNotSupportedException on Spring Boot 2.3.1:

    @GetMapping("/sample-entities/{id}")
    public SampleEntity getSampleEntity(@PathVariable("id") SampleEntity sampleEntity) {        
        return sampleEntity;
    }

Sample project with failing test: https://github.com/naturalprogrammer/boot-data-31-web-support-test

Comment From: wilkinsona

Thanks for the report and sample. This is a duplicate of #22237 and #22104.