There can be many causes for wire stick issues.
For an issue with the wire sticking in the puddle at the end of the weld, it could be the wire continues into the puddle after it is supposed to stop. Monitor the drive wheels at the end of the weld and make sure they stop quickly. I would swap out the i400 & the feeder to rule out a dynamic braking issue.
Could also be too much wire tension in the torch where the extra wire relaxes into the puddle at weld end. Verify proper liner size and length. Temporarily try a slightly larger tip size and see if it makes a difference.
A good Lincoln rep should be able to help and get you in touch with tech support while they sell you the advantages of the more expensive Lincoln wire. Might be worth buying a barrel just to eliminate the wire itself.
In addition to Skooters remarks,
When the distance between the feeder and the nozzle is big, and there is more then one bend in it, the wire will buffer and that extra lenght will come out when the feeder is stopped.
So, make the distance between the nozzle and the feeder as short as possible, keep it as straight as possible and use a lining with a fit as thight as possible.
