Retraction watch was regular reading for me when I was in graduate school.
Unfortunately, in general, things like data fabrication are all too common. A classmate of mine was dismissed late into his PhD when his advisor did some basic sleuthing and caught edited elemental analyses. The advisor already had suspicions, but lab mates saw him using a PDF editor and the advisor just requested copies directly from the lab.
With the pressure involved, the temptation is very real especially if your experiments aren’t going the way you expect. It happened to me, but rather than massaging the data, I just ran with investigation the seeming anomalies and was able to show something beyond a shadow of a doubt that contradicted what my advisor thought should happen actually didn’t, and my seemingly anomalous data was actually correct. That quickly became the focus of my thesis
Of course too there are still the odd things that can frustrate you. I remember looking at .csv files of GC-MS data that were thousands of rows long and thinking how easy it would be to make a peak disappear or add a peak. Of course I would have been caught in about 10 seconds if anyone had pulled the easily-accessible data off the instrument, but the frustration and temptation was certainly there.