Regarding Observation 4304139 may it be that FM signal it is that single horizontal line visible on the waterfall?
I am suspecting that it may be some storm spike but I am not sure.
Thanks for a hint.
@sp6hfe that looks like interference. It is a very short duration and very wide bandwidth. At this frequency I would expect the bandwidth to be narrower. But do some more observations and see if it repeats. Maybe something strange is going on.