I dunno. For me it's not. I've been entering on Friday's and it never triggers. It's just the same crew for Topless Fridays doing the same stuff. I'm guessing if the save file works for you, then the save isn't corrupted. Should I just download v4.00 again?
First of all, the scene is only happening on Friday's evening (i.e. not on Friday's morning or on Friday's afternoon).
Then, the corresponding switch for activating this scene is triggered when the day is changing in the game (i.e. "Resetting dailies"). Which means -for instance- that you can't use the cheat room to change directly the day to Friday and the time to Evening time. If you want to use the cheat room, change the day to Thursday instead, sleep into your bed until Friday, advance the time to Evening time (by the standard ways or with the cheat room), and then go to Carla's Inn.
You can always re-download the game (especially if you've not got the latest version i.e. 0.400.0.3), but anyway the Great Paladin scene is also working with the version 0.400.