In the upper inscription on f17r, there are two words in Voynichese:
oteeeor (otcheor) aim. By the way, the handwriting is identical to the entire You are not allowed to view links.
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oteeeor is a hapax found on f68r2. Assuming that f68r2 describes a sacred lunar month, we can assume that this text is a recommendation such as "harvest this plant only on this day" or "brew this potion only on this day."
otcheor appears 4 times, three times in the botanical section and once in the zodiacal section. Perhaps the meaning of the text will be similar (based on the fact that this word is in the Zodiac).
In any case, there is a motive for the author's abrupt switch to Voynichese - he didn't want to reveal the secret in advance