Facets go missing after updating a record

Every 24 hours we rebuild our index. During this time, we specify these facets (anonymized):

"attr1",
"attr2",
"searchable(attr3)",
"searchable(attr4)",
"searchable(attr5)",
"searchable(attr6)",
"attr7",
"searchable(attr8)",
"searchable(attr9)",
"attr10",
"searchable(attr11)",
"searchable(attr12)",
"searchable(attr13)",
"attr14",
"obj1.attr1",
"obj1.attr2",
"obj1.attr3",
"obj1.attr4",
"obj1.attr5",
"obj2.attr6",
"obj2.attr6",
"attr15",
"obj3.attr1"

When I look in the Algolia Admin console for hte facets on this index, these facets are displayed as expected.

However, after we update any 1 record, the facet changes unexpectedly to this:

attr1
obj1.attr1
obj1.attr2
attr2
attr3
attr4
attr5
attr6
attr7
attr8
attr9
attr10
attr11

That is, 10 of the original 23 facets go missing. All of the searchable ones are gone plus an additional one that is not marked as searchable.

Help! What is going on here?

Hi there,

This is indeed very strange.
Thanks for granting us access, we have emailed you to know more about your indexing process.

Thanks for your patience while we investigate this issue!