Sounds like you had a composite line, where PBS gave you some trips but not enough to get you to min guarantee. It's usually a hint if you're very junior and you get a line with like 19 days off...
In that case they will add reserve days where they need to to get you to the min credit.
When you get your line, if it doesn't add up to min credit, then email CS before the 24th. and let them know where you prefer that they add RSV days. Maybe they will, maybe they won't.
PBS may have given you a day off in your composite line, but the schedulers don't consider your bid when they add the RSV days.