I think I may be having a similar problem. My Pixel 1 recorded a vertical video instead of a horizontal video. I can preview the vertical video just fine in Shotcut v. 19.01.27 on Windows 10, but when I drag it to the timeline, the program crashes. If I try applying a filter to rotate the video -90 degrees and scale it 178% before dragging it, the program still crashes when I try to move the clip to my timeline.
I just wanted to make sure this was the same problem listed above that will be fixed in 19.02.
The new update fixed the problem. Using the Size and Position filter with the rotate filter is still buggy, but I can work around that. Thanks for all the hard work!