The approver user will not be able to approve the approvals in the 'Approvals' widget in the 'approvals' page even though the sysapproval_approver is visible. But the same behavior is not reproduced in the 'approval' page and the user has access to approve the record.
Release or Environment
In the server code at line 17 in the 'approvals' widget, the code is checking if the user can access to write to the state field for sysapproval_approver.
if (app.get(input.target) && app.state.canWrite())
If the user does not have access to the state field, the loop inside the above condition will not be processed.
To resolve the issue, provide access to write to the 'state' field in sysapproval_approver.