Doesn't Run on 8.7.0 in Docker

[angryviking]

After building the plugin for 8.7, it seems to work with Kibana in development mode running on my local machine.
When I try to add this plugin to our 8.7.0 instance running in Docker, I get the following error when I try to connect to Kibana:

Here is the Dockerfile that I am using to build the container

ARG  BASE_REGISTRY=docker.elastic.co
ARG  BASE_IMAGE=kibana/kibana
ARG  BASE_TAG=8.7.0

FROM ${BASE_REGISTRY}/${BASE_IMAGE}:${BASE_TAG} AS builder
ARG  BASE_TAG
USER kibana
COPY kbnSankeyVis-${BASE_TAG}.zip /tmp
COPY customKibanaTheme-${BASE_TAG}.zip /tmp
RUN  bin/kibana-plugin install file:///tmp/kbnSankeyVis-${BASE_TAG}.zip && \
     bin/kibana-plugin install file:///tmp/customKibanaTheme-${BASE_TAG}.zip

FROM ${BASE_REGISTRY}/${BASE_IMAGE}:${BASE_TAG}
COPY --from=builder /usr/share/kibana/plugins plugins/
RUN  bin/kibana --optimize

If I remove just the customKibanaTheme plugin, everything builds and runs fine.