Just curious if this is one of those "Discos are known for this" kind of rust problem.

On the drivers side (LH drive) right at the joint of the interior roof lining and the windshield I have a leak whenever it rains. Looking at the outside of the windshield, there is a gap (on both sides) of the windshield liner, so it looks like water can just get in there freely, which could obviously lead to it rusting over time.

I guess my question is, should the exterior lining go all the way to the edges? And if not, is this fairly common and will just jamming some silicon in there work short term? Seems like it would be a major pain to take the interior roof lining out to repair this, so I am hoping enough silicon will just prevent it from getting in there in the first place.

Pics attached, many thanks in advance for any advice!