Personal Contributions auto-approving claims with null submissions

We have come across examples of personal contribution claims submitted by employees that are being auto-approved by workflow. These claims have no information associated with them and appear as 'null'. After some testing, we have only managed to replicate the issue by pressing submit on the contribution page without submitting any information, so we believe this to be the root cause.

Our approval rules are set up for personal contributions initiated by employee are to go for manager for approval. Actual claim submissions are following the approval rule as expected. But 'null' submissions are not meeting all of the conditions of the employee approval rule (employee claims that should go for approval) but it does meet the conditions for the manager approval rule (manager submits claim on behalf of employee which should auto approve) which is how they are getting auto approved.