Well, I'm not really sure what a "buckle" is but... Do you have a Power Beyond loop on your machine? It sounds like the symptoms for a PB loop that isn't connected up properly. You may also have a poor hydro connection on your SCV.
I'd suggest re-seating all of your hydraulic quick connects as a starting point.
Sounds like a weird hydraulic problem. I think this comes from a bubble in the hydraulic system. From many posts on this forum, I would suggest the following things to try:
1. Disconnect and reconnect your power beyond port if you have one.
2. Run the PTO for a minute or so.
3. Run the loader up and down, same with its bucket.
4. Disconnect the loader and reconnect it, all 4 ports.
"It Bears Repeating Dept": Do all hydraulic connection/disconnection with engine off, hydraulic controls moved through all positions TWICE to completely depressure hydro system. Even a small amount of pressure on a quick connector can cause a difficult connection.