When rewrapping a DCP and burning in subs, it'd be ideal if the font used was the font specified in the original DCP. As far as I can see, at present DCP-o-matic uses a standard font no matter what you put in.

It's theoretically possible that this could lead to character encoding errors if the original font contains a glyph which DCP-o-matic's standard font does not have.

What does definitely happen is that sometimes the positioning of text is thrown off. On occasion DCP-o-matic's font renders bigger than the original which can cause text to run outside of the mask (in e.g. 1.33 pillarboxed in 1.85, the text can render outside the 1.33 frame where in original DCP it was within).

In extreme cases where a subtitle is too big to fit horizontally within the container, the subtitle can fail to render entirely. I've never actually seen this in practice, but can make it happen by setting a stupidly large scale like 500% on the subtitles so lines are too long to fit in the frame.

I don't know how difficult this would be to implement. I imagine it might be tricky, and it's only a minor niggle, so perhaps not worthwhile.