End point at non-K frame

Yes, if you ues K-Frame accuracy mode, K-Frame is only necessary for a segment start, and it's end can be set to arbitrary position with frame accuracy.
i't hard to say what's wrong with a soft you've menioned, as it does not look as something common.

The splitter allows me the choose marker at the position other than K-frame.

The it's trimmed, what does it do?  There is no encoders so the starting point must be K-frame.  However, the end point can be non-K-frame.

The resulting video plays fine.  However, when it's imported into Encore, it will cause Encore to hang.  If I move the end point is set at K-frame instead, it will import fine.

Is there any special handling?

Thanks