Ah, this is happening because Popper is autopositioning the menu (regardless of dropup settings). Setting data-display="static" on your select element (in addition to data-dropup-auto="false") should prevent this from happening.
Thanks that did the trick. It might be worth noting that on the docs.
Note to self: check into setting data-flip="false" on the dropdown button.
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Ah, this is happening because Popper is autopositioning the menu (regardless of dropup settings). Setting
data-display="static"on your select element (in addition todata-dropup-auto="false") should prevent this from happening.