I do think you have a problem here but for someone who says that you can not take the 18-135 in the rain and/or there is no seal between the front and rear element, that is not correct. Just take a look from the PF review and it shows a detail of where the seals are so others should not think that they can not go out in the rain at all. I live in the Philippines and obviously there are torrential downpours here and I have never once had an issue with my WR system on my K-30, but there could be a specific seal problem with your camera, you need to have it serviced.
That being said, yes there are some precautions to take such as, don't be looking skyward while rapidly zooming, which will suck in some rain, but just look down and let gravity do the rest. Of course, in typhoon conditions here, I still take pics, but do try to cover my cam to some extent but I would never take a non WR camera in any extent of any manufacturer. Pentax is great and WR works extremely well so don't let some others make you feel that it is not water resistant at all, it actually really is.
As stated in the review from the PF info:
"The weather sealing on the 18-135 is no gimmick or some mere marketing ploy. It works. The animated .gif above was one of the first things we did with the lens upon starting this review, and since then it hasn't so much as hiccuped for the rest of the testing we've done.
None of the above images will win any awards for sharpness or clarity. But more important than what is technically capable (don't you fret, we'll get to scrutinize and discuss a myriad of comparison tests and sample photos in the following pages),
the above images demonstrate new opportunities afforded by a weather sealed camera-lens combination that otherwise would have been missed thanks to leaving your camera at home or in the bag."
"It is critical to note that none are rated as submersible (despite a few intrepid Pentaxians purposefully dunking their cameras in pools) when it comes to water ingress protection, but rather water spray, light and heavy rain, snow, shower heads, hoses, faucets etc. Zooming, especially extremely quickly, with the lens while wet may increase the chance of water ingress."
Read more at:
Review: Pentax-DA 18-135mm F3.5-5.6 - Weather Sealing | PentaxForums.com Reviews