Why are the in/out frames in the Program monitor while using the slip tool so much smaller now?

What is the Frame Size of your sequence and your media?

As an example, slipping a horizontal clip in a vertical sequence will result in smaller preview images, even if you have scaled the clip to fill the frame.

 

post this in the premiere forum, https://community.adobe.com/p/premiere 

and change your title slightly to avoid a duplicate post error.