Yes, this works! Are there any side effects if I disable either of those options?

comment #1:

> Indeed, when exported as hummus-generated (aka "texmacs native") pdf the attached beamer document may seem to have missing lines. Actually, the lines are present but painted white, and this is due to the slide title being painted white too : if one changes the title font color, the lines become of that color, and if the title is deleted, the lines appear black in the pdf.
>
> It is plausible the issue could just be due to the image itself not properly setting the lines' color before painting them. Also, AFAICT, this issue is a rare case of bad rendering of a pdf image with hummus, which justifies suspecting the image.
>
> In any case, when the issue is present changing the pdf generation preferences can fix it. One can either :
> -turn on the "distill encapsulated pdf images" preference (i.e.  before inclusion with hummus, preprocess the image with gs),
> -deactivate the native pdf export preference (i.e. use gs instead of hummus),

To reproduce:
1. Open the attached tm file.
2. Print or export to pdf and observe the lines in the image are missing.

The pdf image is also attached.