First, I don’t walk in the rain but if I did it still would not be a problem unless the flashlight was dropped in a puddle. The port is usually opposite the button and I carry with the button under thumb so pointing up, port down. If I needed to go into a very wet situation I could always use a different flashlight. If it did get wet, oh well, life goes on. It wouldn’t negate the hundreds of convenient recharges. Most of my lights without charging sit on a shelf. Sorry OP. I’m having a coffee rush. 
I have a similar flashlight: the SP40
last time i used it natural spa with water and sulfur at 40 degrees celsius (104 Fahrenheit), next time i go i will carry the flashlight and take pictures, while the water from the small waterfall falls on my head and my flashlight.
So my experience regarding the waterproofness of this flashlight is more than good, but only my experience remains.
Talk about this flashlight:
Here, too, the cover is stable and pressurized.
Not only is it stable it is also difficult to remove: I have difficulty removing the cover to recharge the flashlight.
I have to use my fingernail under the little rubber tongue to open it, otherwise I can't open it.
However it is obvious, you have to be careful how you use it, if you accidentally remove the cover, water enters, but also the diver water resistent watches if you open the crown accidentally the water enters, these watches are also tested in the laboratory, but they work very well in water .
Then there would be another question: maybe your flashlight is faulty and maybe you should ask for customer service assistance if you think it is appropriate.
Sorry to read that a flashlight flooded, my last flashlight also flooded and I immediately contacted customer service and we talked about it.
I understand how it feels when an instrument fails miserably, but my experience of impereambility of the USB port of the flashlights is really very good, so I repeat that my experience is positive, that's all.
Hope you can solve your problem, thanks for sharing what happened to you.
The idea of on-board charging, especially for traveling, is very appealing but like others have said it isn’t worth the compromised water resistance. This is why my SC31Pro and IF25A have been unable to replace my old Zebralight in my backpack. Now, something like the D25L/D25LR or the above mentioned Acebeam with truly hidden and protected charge ports is one solution. Another would be USB-C rechargable cells. Given that one fits in the light you are using (or the light is designed for it) this is a great option. No problems with water ingress, easily swap cells if needed, no extra charger to carry.
My Zanflare F1 has an excellent USB protection, but the o-rings need to be greased from time to time.
My Sofirn IF25A and SC31pro both have a good protection, if the rubber thing and the port opening re kept free of dust.
The only problem is with the rubber plugs, they may pop out if the light runs hot and the lot of air inside the light expands. This is on one hand a proof it’s really sealed, but on the other hand it shows a huge problem, because once this happens in rain, the moisture has an open entry. In water or in a strong rain, the lights gets better cooling, though.
I’m seriously thinking about cutting / routing a thread into the heads with an o-ring on the bottom and using a simple srew-in plug, but i have not the right tools at the moment.
To totally abandon in internal charger to allow continous using by just swapping batteries is not really a good idea, because usually one can anyway swap the batteries and use an external charger.
Update:
I’ve tried to use a magnetic USB-C power adapter plug and it fits into the cavity!
So, there may be the option to just glue that thing in with MS-polymer and leave the gold-plated contact pads exposed, as they don’t rust, anyway. But I really just like the regular USB-C.
of course, this can access, it never happened to me, but thanks for letting me know.
From next time I will turbo the flashlight for a couple of minutes, open and close the usb cover, so as not to have this problem.
My problem with the USB rechargeable cells is that they are dedicated to a single light (for the most part). Often the lights designed for them cannot use other more common batteries. Also they are expensive, and I have read about many cases where the charging circuit fails early in their life.
I have one light that uses these. I don’t have any desire to buy more.
Yea I’ve done that before too. Actually, I handed my SP36 to someone without an introduction and the first thing he did was hold press the charging port
Some Sofirn headlamps do too. I had a D25L on order and it’s arrived and has a micro USB charge point hidden in the threads one end. The HS20 has USB C hidden under a cap.
i use the clip to point to the ‘on’ button
i THINK you can get waterproof usb ports
i mean haven;t phones had this for years?
iphone and whatnot?
More than likely it’s flashlight companies cutting costs by not using waterproof usb ports. It’s sometime like $1 vs $3.5 in lots of 1,000. I’d gladly pay the difference for a waterproof port but the companies clearly are going for the cheapest option.
Who’s going to care about the difference in price on phones costing upwards of $1,000 or more?