My original subject title for this post was "Why two different searches for apparently same word?" I actually answered that question in the process of creating the pics below (click them if they're blurry), but I now wish to answer the question in the current title.
When I did a search on "ingathering" in Exo. 23:16NASB...

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...which yielded this result...
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...I immediately noticed the absence of a listing for Exo. 34:22NASB. Since these are the two pericopes in Exodus that mention the three pilgrim festivals, I expected them to both appear in the same search. After searching the word in Exo. 34...

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...which yielded this result...
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...I determined that the reason the Exo. 34 verse was absent from the first search was due to a variation in spelling--specifically, the Exo. 34 spelling has an additional yohdh serving as a mater lectionis.
The pic below shows the Exo. 23 spelling from LHI (blue section w/o yohdh)...

...while this is the Exo. 34 spelling (green section w/ yohdh).

The addition of the yohdh (technically a "letter Y" equivalent, but here used as a vowel per mater lectionis) has the effect of changing the pronunciation from short to long. Using my one-to-one Davidic transliteration method, the difference in spelling and pronunciation is:
Exo. 23 - 'aassipph (aah-SIP)
Exo. 34 - 'aassiypph (aah-SEEP)
What I would like is input on is why this difference occurs. Is this a cantillation issue? I notice that the corresponding cantillation mark in orange (see 2 pics above) is on two different words, ("ingathering/harvest" - 'aassiypph in E23 & "feast/festival" - hhagh in E34). If this is the cause of the spelling change, I'd like an explanation. Thanks.
Also, for what it's worth, both LHI (above) and DBLH (below) show the lexeme as being the "full" ML spelling (yellow sections).
