Mazda 6s Stalls & No start

This Mazda 6s (3 L, 125,130km) came in our shop for symptoms of stalling and no start. We have been looking after this 2005 Mazda 6 S for last 2 years. We replaced the battery a few days ago. According to the customer, the car stalled at stoplight, car did not restart, no noise and no cranking. After a few moments, the car restarted and he drove to our shop.
The Mazda started well for us, and show no sign of any problem. I scanned the computer fault codes. It had 2 codes. One is U0121: lost communication to ABS system. And the other one is U0100: communication loss from the engine computer. I searched our database for any similar incidents. I did not find any. I searched further, then I found one case. The communication problem is due o power shortage to computer and abs module.
We found a partially burnt a fuse under the engine hood. It was the fuel pump fuse. This same fuse supplies battery voltage to these units.
As you can see, the fuse receiver side set up is very unusual. One side has its proper contact, but the other side has only a line contact as you can see the picture. So the line contact side of connection has much less contact surface, but it still carry same amount current. The area is too small, and that causes the heat to increase. As you can see the half of fuse pin is melting with heat. This caused intermittent stall and no start. I could not understand why Mazda made it like this. This melting fuse can not be unavoidable unless the fuse holder is fixed.