same thing here, if i select only a portion of an audio files i get the error.
by creating another clip (CMD E) i'm able to perform the audiosuite
happened suddenly on my workhorse machine after using same PT & OS for years. OS 10.12.6 sierra & PT 2019.12.0
but it happened also on another system and PT version in a studio i frequently record. (at least catalina & latest PT Ultimate)
must be my bad vibes...
