The clear answer
No. CELPIP does not penalize accents. The exam scores pronunciation clarity and intelligibility—not accent reduction. A strong accent is fine as long as listeners can understand you.
What CELPIP actually scores
Examiners focus on: clear vowel/consonant sounds, consistent stress patterns, and smooth linking between words. A strong accent with clear articulation scores well. An unclear accent with mumbled words scores poorly.
What to focus on
Spend zero time trying to sound 'native'. Instead, invest in clarity: slow your pace slightly, emphasize key syllables, and practice common sound distinctions (th, r, w, v) that tend to be difficult for non-native speakers.