Function Routing - Sucess only for first invocation

[achatterjee104]

Description
I am creating a vanilla web based spring-cloud-function (3.0.9.RELEASE) application containing multiple functions. I used Spring's built-in router function. Below is my configuration

spring.cloud.function.scan.packages=abhishek.scattered.springcloudfunction
spring.cloud.stream.function.routing.enabled=true

Now when I run the application and invoke the url for the first time, it is working as expected. But for second invocation (and consecutive) it is throwing exception like,
java.lang.IllegalArgumentException: Routing input of type Publisher is not supported per individual values (e.g., message header or POJO). Instead you should use 'spring.cloud.function.definition' or spring.cloud.function.routing-expression' as application properties

After debugging I also found that, for second invocation, it is not able to lookup actual function object from registry (but, for first invocation, as it is creating the function object and populating the registry for first time, it can found), hence the consecutive problem comes.

I am able to replicate this in my testcase as well, but being a new comer in spring-cloud, I am not sure if this is a framework issue or some problem in my code.

I have also posted a question regarding this in stackoverflow

Sample
Please refer to sample project in github,
scattered-spring-cloud-function-router