When working with an SVG (I will email it as I learned in my last post that long SVGs don't work well in this forum) I found the post-nano file neglected to base64 encode one of the fonts, resulting in a very different final result.
I ran the attached SVG file through the web portal for nano. In the original you'll note there are two instaces of "2020" on the X-axis for each graph, but after running through nano (and having the fonts compile et cetera) the 2020s are no longer there (and there is a 2020 in the upper left-hand corner of the resulting SVG)
I tried opening it in Vecta and the "original" looks good, but the "minified" version shows the difference (this is why I suspect the minifier)
I tested just adding a @font-face rule with the base-64 encoded fonts directly into the source file and do not observer this issue (sadly this makes my file much bigger ).
(Edit: I don't see how to get at attached files, so including the SVG source for reference)