What you are training
Say the line out loud and your speaking voice already knows which syllables are stressed. A melody that puts those syllables on strong beats sounds natural; one that puts a weak syllable on the downbeat sounds like a translation, and listeners feel it even when they cannot name it. This is rhythmic prosody, and it is the most common break in first drafts because writers set words to a melody they already had. The fix is a habit: mark the natural stresses, then check where the melody puts its weight. This drill shows a line and a rhythm, asks where the stresses fall, and scores the match. The reveal shows the natural speech stress against the musical stress so the mismatch is visible. Six rounds and you will start hearing dropped stresses in songs on the radio, and fixing them in your own before they reach a demo.
After this drill, the plan: The daily plan runs this on lines from your own catalogue next, so the habit forms on the songs that need it.