I have just noticed that my goalkeeper Amos Burton has lost most of these xp points, he only has 0.22 left in xp even though he had accumulated almost 8 xp.

He wasn't moved to an outfield player during a match? Which would explain the loss of his XP.

That's it, you put him dl then when he returned to the goal there was a dead loss of xp... too bad but unfortunately this happens to some manager and there's nothing to do. Good luck