All Good Things... (1) - S7-E25
Corrected entry: On the Pasteur, when Data reports another ship de-cloaking, he says "It's the Enterprise." He uses a contraction rather than saying "it is." Even though it's in the supposed future, many times Data has pointed out he can not use contractions.
Correction: As you point out, this is in the future. A future where he has mastered emotions. It's assumed he's overcome the contraction limitation as well.
While I can agree that is possible, I find it a bit unlikely. My reasoning is that this occurred in the possible future presented by Q, because he was taking Picard through time. In Generations, he had taken Soong's original design for the emotion chip and improved it. However, he still was not using contractions.
In the episode DataLore, Wesley realises that Lore has taken Data's place because Lore was using contractions and, as Wesley stated, Data never uses them.
All Good Things... (1) - S7-E25
Corrected entry: When Picard is in the past and encounters Data for the first time, he calls him "commander Data". But as can be seen by the insignia on Data's collar (two pips, where a commander has three), he is only a lieutenant at this point. But for some reason nobody corrects this, not even Data, who is exceptionally accurate on all Starfleet protocol.
Correction: Data reported to the Enterprise-D as a Lt. Commander. Referring to him as Commander is an accepted practice.
Correction: Data's use of contractions in the future demonstrates that he has evolved further towards his goal of being more human.