Interlaced transitions?

Hi,

I am new to Shotcut and really impressed - well done!
However, doing first tests with SD PAL and 1080i50 AVCHD material, it looks to me that transitions are always rendered in a progressive way.
I.e. if I set a transition to 4 frames in a 25fps project with interlaced clips, disable “progressive” in the settings and set the export settings accordingly (interlace, top field first), the transition only goes in 4 steps (full frames) instead of 8 frame (half frames) so that the transition does not look really smooth.

I checked this by opening the result in VirtualDub2 with enabled interlaced/yadif/double frame rate filter.

Or did I miss any other interlace setting hidden somewhere in Shotcut?

With kind regards
Joerg