Hi,
Because "You may also like" text comes from Asymmetric Template's language file. Change it via this file:
/language/en-GB/en-GB.tpl_flexible_asymmetric.ini
the line to change is this:
TPL_FLEXIBLE_RELATED_PRODUCT_TITLE="You May Also Like"
Alternatively, you can move the
en-GB.tpl_flexible_asymmetric.ini file to
/pt-PT/ folder and apply your translations on this file:
/language/pt-PT/pt-PT.tpl_flexible_asymmetric.ini
Regards.