I've had 3 campers over the years that experienced this, including a small crack on my current one. I caulked them and never had another problem. ... and NO water intrusion into the cabover section, etc. I too took (take) my camper on rough dirt roads (not 4x4 roads though) and the first time I experienced a crack in the cabover like yours was just after the first year of a brand new 1996 camper. No, it's not desirable and is a bit of a worry but you will know, other than tearing the entire cabover apart, if there is a problem in the future soon enough. The only concern I would have at this point is that after all these years it just now is appearing. No way to really know what is going on "under the skin." Just keep an eye on it. Yes, the struts help with the porpoising, but they are not load bearing. They help with the bounce and stress a bit too. Seal it, watch it and go camping!!! Well, at least that's what I did all these years! :)
Dak
