I remember there was a series of articles several years ago that German intelligence officers generated a lot activity in far-right websites. To the point that frequently it was mostly undercover „extremists“ discussing between themselves.
The closest article I can quickly find is about Germany intelligence informants doing the same in meatspace though.
> There was a "risk that sources of the intelligence service (Office for the Protection of the Constitution) could goad each other on to undertake bigger actions;" in other words, the system threatened to create an "incendiary effect."