This is a distributor issue; our lead time in the pricebook is 2 weeks.
The Avnet Express site says 1300 are on backorder and can ship roughly a month from now: Broadcom BCM20732S, 32QFN - Avnet Express
The distributor sales person needs to work with their inside sales and corporate product management team to understand why 16 weeks is the lead time. Doesn't make sense.
Mouser may have stock today that can hold you over for a little bit: Broadcom BCM20732S RF System on a Chip - SoC | Mouser