While working around the annoying lack of proper support of layers within presentation builder
-- with pages (select the desired layers for a slide, duplicate the page, rename it to “slide-1”, go back to the original, select the desired layers for the next slide, duplicate the page, rename it to “slide-2”, etc)
-- and then, trying to export the slide pages…
...to PDF, I get some ghost shapes:

(I don’t know where this the dark rectangle comes from or how to get rid of it)
...and to PNG, the quality just fecal:

(all the boxes are actually the same, and should be like the top right one)
...So, why? (I am willing to share my document with anyone willing to investigate this)
p.s. I’ve been a paying user for many years, and my functionality requirements haven’t changed too much, so, I have no idea what the guys have been working on there for all these years, since doing something which is not completely primitive results in disappointment like this.