When I keyframe the position, everything goes wobbly. Even if I keyframe every single frame, it's still a mess. Is there a way to unlink it from the tracking data for a specific timeframe?
Also, acting a bit less condescending would suit you.
You could split it, but if the camera is moving so that the text should be off screen, the text SHOULD move off of the screen.
Could you post an example video of its behavior or show us some screenshots?
How did you create the text in the environment?
If you have a good Camera Track then you can attach your text layer to some geometry in your scene. If the camera pans past this geometry then the text layer will follow it off screen provided that you set up your targets properly and you have a good camera track. Make sure that you set an origin and ground plane.
It sounds to me like you didn't get a good camera track. Animation of a 3D layer in a scene that is camera tracked may give you some very odd results if there is camera shake and your target isn't perfectly attached to the geometry in the scene. I'd guess from your description that you are either trying to animate the position of the text in the shot or that you didn't get a good track in the first place. Carefully review your workflow and if you cannot solve the issue please post a detailed description of your workflow and a screenshot showing the modified properties of the layers that are giving you problems. Just select them and press the U key twice then drag your screenshot into the Reply field on this forum so we can have a chance to give you some help.
Maybe this mini tutorial will help:
Thank you for taking the time to give a more extensive answer than the first. I indeed did not get a good 3D camera track, which is what resulted in this issue. I probably could have made this more clear in my first post. However, as this is not my footage, I cannot re-record to get a better camera track.
In the end I "fixed" it by ditching the off-screen part altogether, so I just now cut-in with the tracked object already in the scene.
What would you normally do with a scene that didn't track properly? Or tracked properly for the most part but became messy once stuff moved to the side of the screen?
Would you (somehow?) fix the tracking, or just adjust manually?
And if adjusting manually, how? By just keyframing the position and place each frame by hand?
When the track is not good, you can improve the track by excluding trackpoints that are not accurate.
Finally, if all you need is inserting a single 2D object like a text, planar tracking with mocha is a good alternative (given that you have a plane in your scene that you can track where you want to insert the text). In general, tracking a single plane is much easier than tracking the camera and the results will usually be more accurate. Hence, only track the camera if it is really necessary.
This is a good starting point to learn mocha