Monster Motor Shield VNH2SP30, motor 1 reverse not working

I'm using this one

https://protosupplies.com/product/vnh2sp30-dual-monster-motor-shield/

Motor 2 runs fine in forward and reverse, but motor 1 will only run in forward direction. Pins 7 and 8 set the direction for motor 1, [pin 7 HIGH and pin 8 LOW] or [pin 7 LOW and pin8 HIGH]. Pins 4 and 9 are used for motor 2. Pin 7 is set to HIGH as I can measure 5V against GND but the led on the shield that indicates reverse direction will not lit.

Is there any problem with the board or am I doing something wrong? I used three different sketches to test it though they do basically the same, setting the enable pins for both motors and then set the directions accordingly, this one for example:

Tutorial for Monster Motor Shield VNH2SP30

I tested this sketch for monitoring the leds that indicate direction for both motors, that you can see in the video (link). As you can see, boths leds at the right show both turning directions of motor 2, bt to the left, only the forward led is lit.

(sketch)

(video)

I'd appreciate any help!

You use the most easy way for You using links like You do. Not all helpers will take on the job digging up all the information from them.

Code should be presented here using IDE autoformat and code tags.

Most helpers don't spend time watching videos and especially not tutorials. There are lots of other members to answer...

Replace telling about pins "here and there" with proper schematics, please.