Some of the inexpensive servos do that. I don't know of a fix other than changing out the servos with ones that don't. I know the EZ-Robot HDD servos don't do that, and they're far quieter than all other servos i've ever used. Oh, and they have burnout protection. But, you might find some other manufacturer servos do that operate similarly - let me know if you do

I have custom robot using EZ Robot servos. 
I reversed the mounting of the vertical head servo so that when powering up, the head jerks backwards instead of forwards causing no damage.

All of a sudden the AimI bot Control is corrupt producing the following error... I cannot delete the Control either.
Version: 2020.01.05.00

System.TypeLoadException: Could not load type 'EZ_Builder.Scripting.ScriptManager' from assembly 'ARC, Version=2015.8.9.0, Culture=neutral, PublicKeyToken=c3a3457c97d352d9'.
at AimlBotter.FormMain.FormMain_FormClosing(Object sender, FormClosingEventArgs e)
at System.Windows.Forms.Form.OnFormClosing(FormClosingEventArgs e)
at System.Windows.Forms.Form.WmClose(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

1) Your servos are not HDD. They would be hd. 

2) by selecting to manually press the update plugin button, that plugin was updated. The button presented to you titled update when the software loaded will update when the button is pressed. all plugins are being updated for arc. Your options are to Update your software to ARC beta. Or manually delete the plugin from your plugin folder. Which is \users\public\documents\ez-builder\plugins

All my servos are TP-405 HDD.
I need the previous version of Aiml bot because if I delete the plugin, my project won't load. Is this available to download?

I edited my project file using Notepad and deleted all references to Aimlbot. Drastic but seem to work

Thanks. Solutions outlined above worked.

1) Update to ARC for plugin compatibility and new features

2) I might be misunderstanding if you're already using the HDD servos. Which one of these makes the servos "jump"....
 - power being switched on?
 - connecting with the CONNECT button in the software?

When I turn the power on, both head servos (horiz and vert) jump about 10-15 degrees. If I turn the power off and on again, they will jump again another 10-15 degrees. I can keep doing this until they can move no further. The robot's servos are set to 90 degrees when connecting and disconnecting within the software.

You can verify the servos have HDD on their label? (Not HD)

Bought from EZRobot...
https://www.ez-robot.com/Shop/AccessoriesDetails.aspx?prevCat=9&productNumber=7

I understand they are from the company ezrobot. While we’re not that company and we make the software for the robot, I’m curious about why the servos twitch. Do they read HDD on the servo? We did the software for the ezrobot servos and I can’t imagine how the HDD labeled servos can ever twitch. If they read HD, then they’d twitch because those old HD servos did 

the HDD servos can never ever twitch

They definitely say HDD on the servo. I can live with it now I have turned the servo around. I wonder if they do the same thing with the IOTiny. I do have one to use later for a similar project. But I'm using the EVBv-4 for this robot,.

It’s from applying power, not the controller. The controller doesn’t send a signal it has been instructed to. That was the experience with old ezrobot hd and other similar hobby servos. Which was the reason we programmed the HDD servos to not do that, and to not vibrate or make noise. so I’m confused of why the HDD servos you have are twitching. The ezrobot servos with the sticker hd would twitch, but not the HDD. 

wish there was something more I could help you with about this. It’s got me boggled lol

well hopefully the solution you have works for your application with the servos you got! Fingers crossed for ya

Seems you were correct. I went to swap the servo for another in case it was faulty.
Somehow this one is a HD servo whereas all the others are HDD. Can't imagine where this one came from as I thought they were all part of my latest purchase. I couldn't see it properly until I took it out of the container it was housed in, so I assumed it was like the others. Changing this servo has cured the jerking problem. Sorry about that. You can sleep easy now!

Wooo thanks for that! I was ready to chat with our engineer who originally designed the servos to find out how it could possibly twitch - that saved him a panic