Plugin Automation turns itself off???

[Hardtoe]

Ok, this is something which has bothered me for a long time, but I have never gotten to the bottom of.

Some plug-ins - particularly the Sound Toys bundle, keep overriding the automation, like I had just tweaked a parameter live, but I haven't.

It is particularly annoying, as I'm never sure if the song will render correctly.

In fact after I render, the "back to arrangement" button (by the transport controls) is often red, meaning I don't know what the heck it hasn't done.

Anyone know why this is and how to stop it?

Driving me nutz!

Thanks