I’ve had one of these in place for 10 years

It was dripping inside along this rafter (marked in red):

I had a look at the rubber seal and they seem fine but noticed that there is a slight gap at the top of the rafter here. There also seems to be some residue:

I can see this residue on other joins too:

Why type of sealant/adhesive is this likely to be and does it need to be resealed after 10 years?
I’d appreciate your advice on this.

It was dripping inside along this rafter (marked in red):

I had a look at the rubber seal and they seem fine but noticed that there is a slight gap at the top of the rafter here. There also seems to be some residue:

I can see this residue on other joins too:

Why type of sealant/adhesive is this likely to be and does it need to be resealed after 10 years?
I’d appreciate your advice on this.
