TYPO3 Core

Have you perhaps forgotten the markers in the template?

<!--TYPO3SEARCH_begin-->
<!--TYPO3SEARCH_end-->

https://docs.typo3.org/c/typo3/cms-indexed-search/main/en-us/TechnicalDetails/HtmlContent/Index.html#html-content

This simple example works for me: I'm on 12.0.0 though. But should be the same.

page = PAGE
page.config.index_enable = 1

page.10 = TEXT
page.10.value (
   <!--TYPO3SEARCH_begin-->
)

page.100 = CONTENT
page.100 {
    table = tt_content
    select {
        orderBy = sorting
        where = {#colPos}=0
    }
}

page.1000 = TEXT
page.1000.value (
   <!--TYPO3SEARCH_end-->
)    

@Tomas Norre Mikkelsen No, I didn't add the markers, because these are optional. But I've checked it in TYPO3 v11 (without markers), worked as expected (text was found via search).

So you are saying, the problem appears in v10, but not in v11 with the same test scenario?

@Sybille Peters Yes, I've checked the same test scenario in v11