The Prophet ﷺ used to read the verse "Is there any that will receive admonition (muddakir)? " that is with doubling of consonant [(dal)(d)]. Abu Dawud said: The word muddakir may be pronounced as mim (m) with a short vowel u. (dal)(d) with a short vowel and kaf (k) with a short vowel i.
أَنَّ النَّبِيَّ ﷺ كَانَ يَقْرَؤُهَا { فَهَلْ مِنْ مُدَّكِرٍ } يَعْنِي مُثَقَّلاً