A hint of a problem.
The headache she'd had for the past two days had finally abated and Jean decided that since it was gone, it was a fine day to do some practice.  She felt weak since she'd return and she accounted for it in her sad amount of training.  Abilities were one thing, but you had to use them to be good with them.  She knew that and she knew that she'd simply gotten lazy, her mind turning flabby like an ab or an arm might.  She left Scott a note to let him know where she was--he'd been sleeping and while she could crawl into his head anytime she wanted, notes were still a sweet way to communicate--and then took off for the Danger Room.

A full-service workout was what she wanted so she started with low level drills.  Kid stuff, really, the kind of things they started students on.  Of course they were easily beaten and she steadily worked on more and more complicated scenarios, but instead of defeating them soundly, Jean had...trouble.  For the fourth simulation in a row, her telekineses failed, leaving her for dead in the simulation.  Suddenly, the room shut down.  It was the failsafe they had installed, but now an alert would be sent out that someone was practicing and in over their head.

And Jean should not have been in over her head.