The first glyph of every line – a hint at a cipher?

[nablator]

I'm not quite sure I understand you correctly. Are you saying there's no statistical evidence to show that the text in the individual sections (Herbal, Astro, Recipes, etc.) behaves differently than in other sections?

No, I meant we don't have anything linking the first glyph of lines to anything else (a global property, not local, of the same line/paragraph/page) AFAIK, so if there is a cipher we have no clue if it uses this first glyph as a key or in any other way that implies measurable consequences on the whole line/paragraph/page.

Actually this may be what you have discovered, but you wrote "this is not yet statistically significant".

Some bigrams appear to be highly group-specific (op, yp, ed); there are clear differences here.

Any rule or correlation like: lines/paragraphs/pages starting with <some glyph> have consistently more/less <some glyph or pattern> than other lines/paragraphs/pages could be helpful.