Strange error with google-api-client in google app engine app

Question

We're restructuring our web app, which runs on GAE. The POM was changed a bit. But no significant other changes.

Now we get this strange error on one page of the app:

You are currently running with version 2.2.0 of google-api-client. You need at least version 1.31.1 of google-api-client to run version 1.32.1 of the Cloud Storage JSON API library.

What does this mean?

We weren't specifying a specific version of google-api-client in the POM. However we did at a dependencymanagement section, which I have a feeling has something to do with this error.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.google.cloud</groupId>
            <artifactId>libraries-bom</artifactId>
            <version>26.29.0</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

To resolve the problem I added this back into the POM.

<dependency>
    <groupId>com.google.api-client</groupId>
    <artifactId>google-api-client</artifactId>
    <version>1.32.1</version>
</dependency>

However, I would like to know what is going on. Thanks.