Chopin seems to be doing something unusual with several of the slurs in the Etude op. 25 no. 4.
Examples 1 and 2 are from the composer's autograph. What can be the logic behind:

- Chopin Etude op 25 no 4 slurs 1.jpg (32.55 KiB) Viewed 4431 times

- Chopin Etude op 25 no 4 slurs 2.jpg (34.95 KiB) Viewed 4431 times
The slur at * in example 1 overshoots the last note of the three-note slurred group by a mile. Chopin does tend to begin his slurs early and end them late as can also be seen in the examples, but not like this. That something is afoot is confirmed at ** in example 2, in which a slur is used for a single note!
Examples 3 and 4 are by Chopin's copyist, Julius Fontana, with extensive changes by Chopin, which can be seen at **** and *****.

- Chopin Etude op 25 no 4 slurs 3.jpg (22.44 KiB) Viewed 4431 times

- Chopin Etude op 25 no 4 slurs 4.jpg (30.72 KiB) Viewed 4431 times
At *** in example 3 the copyist extends the slur to the end of the measure in imitation of Chopin's notation. At **** we see a correction by Chopin extending a slur to the end of the measure that the copyist made too short. These overly long slurs are clearly intentional.
Chopin is concerned that the player hold the sustained melody notes completely through to the end of each measure and past the staccato accompaniment in both hands. His solution by means of this unusual slurring is an illustration of the creativity that some composers have used in expressing themselves with our notational system.
Another example of Chopin's logic concerns the staccato dots which might appear chaotic in example 1. Chopin was probably the most prone to careless error of any of the greatest composers; but only about mundane matters, not concepts.
In example 1 Chopin has decided to abbreviate the constantly staccato accompaniment notes in the right hand by writing
staccato below and
legato above the upper staff rather than constant wedges used in the left hand. However, concerned that players unaccustomed to this unique new piano texture might apply the slurs above the melody to some of the staccato accompaniment notes causes him to write in a few remaining staccato dots in measure 1, 2 and 4. When the melody is resting as at the beginning of m. 2, he is concerned that the player might incorporate the accompaniment into the melody and clarifies this with a staccato dot. The staccato dot over the second eighth note of the melody in of m. 3 is quite interesting. He is reinforcing the break between the two short slurred groups as a precaution, since his use of very short abruptly interrupted melodic groups is unusual and might be misunderstood by the players of that time. After a few such clarifications, these precautionary staccato dots disappear completely in the rest of the piece.