When some users trigger an approval for a task record, the workflow activity is marked as skipped and allows the workflow to continue without approval.
Madrid Patch 1
The is a before query business rule on the sysapproval_approver table that prevents the user who triggered to approval from querying. When the approval activity cannot query the approval record, it assumes no approval is needed and gets marked as skipped.
Modify or deactivate the before query business rule on the sysapproval_approver table.