At the start of th enight we got confusing signals. Some images were ok (pointing images, first science image 814238). Then Image 814239 had stars elongated to the right side. The next ones, 240-244, seemed normal. Image 245 is  bad with low number of counts,  no stars, and a line pattern.  246 again had stars with stars elongated toward the right side. 247 is similar to 245. We did a SISPI restart here. Then 250-251 were normal. And we got back to the same pattern as 245 and 247 in image 252.

Although initially we thought of a possible  electronic problem or a tracking problem, a  possibility is that 245, 247 and 252 are saturated due to clouds and full moon. Because of that possibility we stopped observations until conditions improved (it was partially cloudy up to that moment).   Indeed, no problem appeared after sky got clear a few hours later. Not sure yet what happened in images 239 and 246 (stars elongated toward one side).