Hello, it's my first post and I didn't find a better section to post this if this is not the place excuse me.
On topic
I have a walking foot machine, a new one I have set it, but there's a problem occurring :
Whenever I try to lockstitch the thread underneath bunches up and is happening only when I reverse
Somehow the above thread is pulled under without any signs of other problems
My forward/reverse stitches are perfectly matching
Upper tension and bottom tension besides this are perfect and in unison
I have played with the hook also to see if it's misaligned or out of time, but I don't see anything wrong with it
Have tried different size of needles and thread, but without any success
Tried the tighten the top tension and its improving abit, but then the botton thread is showing ontop
Providing 4 pictures, last one is when I sew and then turn the fabric which makes a perfect stitch formation
I will be really thankful if you have any suggestions or have experienced similar problems