Please help me) Leaking from roof

[Kevin_kevin]

Hello,
We purchased a property which has an old manufactured house which was manufactured before 1976.

I saw few spot inside manufactured house leak from roof when it rained a lot last time.

I went up to roof, and I couldn't find crack in the area.
However I saw there were vents(please check attached file-IMG_0355) around the area, so I think water might leak from those vents. If it rains and wind a lot, for the shape of vents, I think it is easy for rain to go inside the vent.

Please let me know if this kind of vents can be the reason. Please recommend a good vent which prevents leak from rain

Also, I saw there was another vent(IMG_0362) on the roof. I don't remember if there was leak around the vent.
However the shape of vent looks like that it will not block any rain if it winds.
Please let me know what it is, and if I need to change.

Thank you.