Built image does not contain a layer for USER instruction

[meinenec]

Actual behavior
Image built in kaniko does not contain a layer for the USER instruction. The user exists and a whoami shows the container running as the desired user, but there is no layer present when running docker history <image>

Expected behavior
I expect a layer to show the user being set.

To Reproduce
Steps to reproduce the behavior:

1. build image docker run -v "$PWD":/workspace gcr.io/kaniko-project/executor:v1.6.0 --context dir:///workspace/ --destination image:local --no-push --tarPath=./image.tar
2. load image docker load -i image.tar
3. check layers docker history image:local

IMAGE          CREATED         CREATED BY                                      SIZE      COMMENT
<missing>      292 years ago   RUN addgroup -S appgroup && adduser -S testu…   4.68kB
<missing>      5 weeks ago     /bin/sh -c #(nop)  CMD ["/bin/sh"]              0B
<missing>      5 weeks ago     /bin/sh -c #(nop) ADD file:8ec69d882e7f29f06…   5.61MB

Compared to docker

1. docker build -t image:local .
2. docker history image:local

IMAGE          CREATED         CREATED BY                                      SIZE      COMMENT
c1fc0aad2f36   9 seconds ago   USER testuser                                   0B        buildkit.dockerfile.v0
<missing>      9 seconds ago   RUN /bin/sh -c addgroup -S appgroup && addus…   4.68kB    buildkit.dockerfile.v0
<missing>      5 weeks ago     /bin/sh -c #(nop)  CMD ["/bin/sh"]              0B
<missing>      5 weeks ago     /bin/sh -c #(nop) ADD file:8ec69d882e7f29f06…   5.61MB

Additional Information
Dockerfile:

FROM alpine:latest

RUN addgroup -S appgroup && adduser -S testuser -G appgroup

USER testuser

Image version:

docker pull gcr.io/kaniko-project/executor:v1.6.0
v1.6.0: Pulling from kaniko-project/executor
Digest: sha256:0fae223f496525e31226cde473ec77ed15abfa8cbabff5ff5bf1c5268355bbb0
Status: Image is up to date for gcr.io/kaniko-project/executor:v1.6.0
gcr.io/kaniko-project/executor:v1.6.0

Triage Notes for the Maintainers

Description	Yes/No
Please check if this a new feature you are proposing
Please check if the build works in docker but not in kaniko
Please check if this error is seen when you use --cache flag
Please check if your dockerfile is a multistage dockerfile