Hello!
In Illustrator our Huion Tablet acts as if we are right-clicking every time the pen touches the tablet. We have been troubleshooting this issue for a while. I have found a post from 2018 - in which the user was experiencing the EXACT same problem. I am pasting that info. in here for anyone who might have a solution. It seems to be an issue within AI as it is not a problem in PS. I am a high school teacher and do not have access to support within Adobe CC - someone is designated IT - who that might be in the county is beyond me.
Here is where we started - same issue - no resolution. Any help is BEYOND appreciated.
Currently I'm using a Huion graphic tablet. Everything works fine outside Illustrator, including Photoshop.
In Illustrator, once I enable "Support TabletPC" in the driver section for pen sensitivity, holding down the pen causes the circle to appear as well as the right click menu once I let go.
I have disabled "Press and Hold" in the control panel and I don't have this issue anywhere else except Illustrator.
I'm not sure if there's a setting inside Illustrator that I need to change in order for it to work.