When importing session data from a different protools session file (which is part of the same overall session folder), the imported tracks' fades are "rendered" as audio, not calculated from scratch . Not only is this incredibly slow to the point of not being practical and a sloppy way to handle session data, it also causes ProTools to become highly unstable when the amount of fades is huge (e.g. takes RAM hostage)
This is something that happens in post production a lot - this is, having different session files saved within one overall session folder, so this bug can be very detrimental to importing session data for large-format TV and feature work.
Fades should always be treated fades, never as audio files. 100% calculated from scratch, no matter how the edits are being imported or sessions are being combined.