the graphical representation is in sync with the values in the info view and also in the inspector/plugin window, so it is unfortunately not only a graphical bug, if you were trying to say that.
I’m using 10.5 pro and just had a similar issue. I was writing automation for the eq and changed the frequency of the band between 200 and 400 Hz. These were only tiny changes and let’s say 20 through the whole song. After stoping the writing the whole automation was smashed down to 6 points and the resulting curve was globally maybe ok, but not in detail.
Finally I was down to the settings of automation (F6 by default) and set the reduction level to 0. Job done! Everything remains, how it was recorded.
I’m not 100% sure if the reduction level might help in your case, but there are more settings, which could apply.