I read the following post about the rules for pronouncing the letter "d"in German. However, it doesn't seem to address a stark difference I hear between German speakers when the word has a "d" in it right before "en" as the final syllable.
For example, take the word "gefunden". At first, most speakers I heard pronounced it the way an American speaker like myself would expect it to be pronounced, with the syllables split as shown below, and the final syllable being fully voiced with a normal release of air:
However, listening to other speakers I started to hear this pronunciation:
With the "d" being shifted onto the end of the second syllable and taking on a "t" sound, since the speaker does a full, quick glottal stop before voicing the final "en". In addition, the final "en" is not fully voice with a release of air, but instead is "passively" released with a sound that seems to indicate that the mouth stays closed while voicing the final "n" sound. The rhythm of the last two syllables feels similar to the way Italians micro-pause between a pair of consecutive "t"'s in a name like Matteo.
Am I right in my aural perception of this variance in pronunciation? If so, what is the most common form used and are there any regional guidelines between pronunciations? Note, all of the pronunciations on Forvo have the first form, but I have definitely heard the second form in a few YouTube videos with native German speakers, and a few modern German songs.