Sliding Gate Mis-Aligned After Repairs

I agree with Steve's comments.
That being said steel has a memory.
When yo build something like your gates they are clamped together or built in a fixture to maintain form while welding.
If the person who cut out the rotted sections failed to temporary weld something to maintain the structural shape that's what looks like the problem.
Those gates are designed to hang and roll from the top channel.
The bottom rollers are to keep them from swinging in and out.