Hey sorry for the very late reply. I am still coming across this issue but it happens for me when I have a flexible field inside a repeater.
if (have_rows('tab_content')){
while(have_rows('tab_content')){
$tabContent[$i]['tab_name'] = get_sub_field('tab_name');
$tabContent[$i]['tab_description'] = get_sub_field('tab_description');
if(have_rows('content')){
while(have_rows('content')){
the_row();
$currentLayout = get_row_layout();
$tabData['row'] = get_row(true); // Information in this is cached
$tabData['content_columns'] = get_sub_field('content_columns'); // Works if I directly call it like this
$tabContent[$i]['tab_content_layouts'][] = Render('page-flex__'.$currentLayout.'.twig', $tabData);
}//end while
}//end if
$i++;
}//end while
}//end if
//Render main with $tabContent
$data['tab_content'] = $tabContent;
Render('page-section-layout.twig', $data)
I am using ACF Pro version 5.6.10