App stops when too many transactions to be signed

### Describe the problem you discovered

The application shuts down if there are too many transactions to sign.

### Describe the solution you'd like

_No response_

Start by reproducing the shutdown with a workload containing many transactions to be signed, then inspect the signing flow and application logs to identify where it stops. Done means the application remains running and handles an excessive signing workload without shutting down.

Written by the indexing model from the issue text.