Bitbucket pipeline deploying serverless stack fails - bitbucket-pipelines

Question

I've been able to deploy serverless-stack applications over to AWS via Bitbucket pipeline.
Basically the pipeline triggers the build every merge to the main branch – usual stuff.
The problem starts with the following script:
npm run deploy -- --stage qa --verbose
There are going to be a random set of stacks successfully deployed e.g.
Building
...
...
...
Building function src/projects/queue.roleCreation
Followed by a series of deployment related output:
Deploying stacks
intr-armada-X | CREATE_IN_PROGRESS | AWS::ApiGatewayV2::Route | CountryRouteGETXXXXX | Resource creation Initiated
intr-armada-X | CREATE_COMPLETE | AWS::ApiGatewayV2::Route | CountryRouteGETXXXXX
Checking stack status intr-armada-X
✅ intr-armada-X
The above and a few others were a success, however, there tends to be a random list of failures as well (I say random because the next time I redeploy (same pipeline and build number), it completes.
deploy stack: done intr-armada-Y {
status: 'failed',
statusReason: undefined,
account: undefined,
outputs: undefined,
exports: undefined
}
❌ intr-armada-Y failed: The intr-armada-Y stack failed to deploy.
deploy stack: poll stack status: unknown
deploy stack: poll stack status: unknown
deploy stack: poll stack status: unknown
deploy stack: poll stack status: unknown
deploy stack: run cdk deploy: exited with code null
deploy stack: run cdk deploy: exited with code null
deploy stack: run cdk deploy: exited with code null
deploy stack: run cdk deploy: exited with code null
deploy stack: poll stack status: cp exited
...and a few more others...
Our pipeline includes more than a dozen separate microservices deployed to AWS (lambda functions for proxies to API Gateway)
I have searched and even updated SST to v1 recently to see if it resolves the issue, but no dice. Same errors.
Any help would be greatly appreciated!