Tuning FX Dream Line loose component internally

Noobie with first PCP here, which is the Dream Line Lite 30 cal. I have not changed any of the factory settings except from the front power wheel changing from 25 / 30 to 177 / 22 to Low. Less than 200 pellets shot, and filled up the tank three times, never filling over 250.

after filling for the third time yesterday, there is now something loose internally, and sliding back and fourth through the body when held straight up and down,

Rifle still shoots true,

any suggestions on what is inside sliding around and how to correct?
 
The only place I can imagine, internally, where something could be falling around, is in the main action body. There are some pins and screws associated with the trigger, safety, and side lever, but it seems something wouldn't be working right if a piece had fallen loose. I would just remove the trigger assembly, then the hammer and spring....see what falls out.