fix double firing of schedules at initial interval

.changeset/blue-comics-prove.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Fixed double firing of cron schedules in cases where the current time matched the initial interval.

packages/effect/src/internal/schedule.ts

@@ -432,18 +432,10 @@ export const cron = (expression: string | Cron.Cron): Schedule.Schedule<[number,
 
       const cron = parsed.right
       const date = new Date(now)
-
-      let next: number
-      if (initial && Cron.match(cron, date)) {
-        next = now
-      } else {
-        const result = Cron.next(cron, date)
-        next = result.getTime()
-      }
-
+      const next = initial && Cron.match(cron, date) ? now : Cron.next(cron, date).getTime()
       const start = beginningOfMinute(next)
       const end = endOfMinute(next)
-      const interval = Interval.make(start, end)
+      const interval = initial ? Interval.make(start + 60000, end + 60000) : Interval.make(start, end)
       return core.succeed([
         [false, [next, start, end]],
         [start, end],