gcloud app deploy source-context.json SHA mismatch

I have a Python 3 project which I am hosting on Google AppEngine Standard. Until a couple of days ago I was able to deploy normally (right since I did the initial setup in July 2019). Now I'm getting the following response:

starting build "abc" FETCHSOURCE BUILD Starting Step #0 - "fetcher" Step #0 - "fetcher": Already have image (with digest): gcr.io/cloud-builders/gcs-fetcher Step #0 - "fetcher": Fetching manifest gs://staging.my-project.appspot.com/ae/xxx/manifest.json. Step #0 - "fetcher": Processing 312 files. Step #0 - "fetcher": Failed to fetch gs://staging.my-project.appspot.com/xxx, will no longer retry: fetching "gs://staging.my-project.appspot.com/xxx" with timeout 1h0m0s to temp file "/workspace/.download/staging.my-project.appspot.com-xxx": source-context.json SHA mismatch, got "xxx", want "yyy" Step #0 - "fetcher": Failed to download at least one file. Cannot continue. Finished Step #0 - "fetcher" ERROR ERROR: build step 0 "gcr.io/cloud-builders/gcs-fetcher" failed: step exited with non-zero status: 1 

Any idea why this would be happening and how to fix it?

P.S. I use the following command for deployment:

gcloud --project my-project app deploy app.yaml 

My gcloud versions are:

Google Cloud SDK 260.0.0 beta 2019.05.17 bq 2.0.47 core 2019.08.23 gsutil 4.42