People had been reporting these for years, but no scientist believed it until the phenomenon had been captured with high-speed cameras. A few very skilled amateurs knowing where to look with good SLR’s have recorded them. Another thing that was thought to be impossible were flashes on the moon reported visually by observers for years. These have now been recorded be camera and I believe that new craters have been found.
There is a fringe theory that some of the craters we see on the moon and other planets are not actually impact craters, but are produced by high energy electrical arcs, so that would be interesting if they found new craters that corresponded to those flashes.
Here’s an old video demonstrating how electric discharges can form similar crater shapes to some that we see on other planets:
https://www.youtube.com/watch?v=S2-NShfWUpc