Since the update it’s worked fine for me. I just tested on a flexible content field with 23 layouts and a lot of fields in the layouts.
I don’t have any other ACF Plugins installed. I’d suggest seeing if maybe something else is causing your issue.
i believe it was addressed in 5.8.2 Are you still seeing it @mroesele ?
FYI, I believe you got file and and line number mixed up.
advanced-custom-fields-pro/includes/acf-field-group-functions.php
line 1032
wow! Great find and thank you for doing so much leg work John!