Yes, "again" because the price was first adjusted back in April this year.
To be exact, the price hike will affect new shipments of bottle paints currently priced at 120/150 Yen effective this December onwards. The new price will be 160 Yen (exclusive of tax, 168 Yen inclusive of tax).
There's no official announcement to be found on Mr. Hobby's website, yet. This news is from Mercury Staff - Diary of a Store Manager, backed by Hatera Diary (scroll all the way to the bottom to see this news).
Regardless of the reason behind the hike again, and regardless of the mere 10 Yen hike, it's a sign of storm hitting the Gunpla market (and the hobby world in general actually), one which we can't escape.
*sigh*
