Just to clarify. When you preview the project in a browser either using the preview button or from an exported project. Does the animations start after 4 seconds or do you have to interact with it to start the animations.
If any of the above then you should not expect the exported video to show the animations.
Or should/does the Animations start on page load within 4 seconds and without any user interaction to start them.
If the latter then you should expect the exported video to show the animations.
Exporting Video does not start animations that require an action, if you do not have actions that start onload then you will need to add them temporarily.
Hope that make sense.