Hi @vik_splunk, this was resolved on our end. I've forgotten about this question and failed to post the solution. But here is what we did to resolve this.
Note: This issue is happening since the input cannot cope up with the large number of messages.
To fix this, just clone your existing inputs that is is supposedly getting this messages.
The answer we have been looking for is under the troubleshooting guide of the app.
https://docs.splunk.com/Documentation/AddOns/released/GoogleCloud/Troubleshoot
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