It's actually not uncommon.
- Addicted to you was released about 8 months after First Love.
- traveling was released about 8 months after Distance.
- COLORS was released about 7.5 months after DEEP RIVER.
- Boku wa Kuma was released 5 months after ULTRA BLUE.
With the exception of HEART STATION, this time it's about the same (just slightly over 9 months).
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