Active shade render deletes timeline cache

[tyFlow]

The only time this happens is if something dependent on the flow has a render-only setting. For example, if you add a Turbosmooth to an object that particles are scattered on, then change the turbosmooth to enabled-in-render-only, when renders begin the object will change (get smoothed) and thus that will trigger a flow reset. So check for that type of thing in your scene.

In the tyFlow Debugging rollout you can turn on 'print sim reset info' to have reset notifications get printed to the listener when they occur. This may help you track down which object is causing the problem.