While some portion of the Vega 10 GPUs are packaged by Advanced Semiconductor Engineering (ASE), the report indicates the majority of the chip packages is put together by SPIL and that this will remain the case with the mainstream Vega 11 lineup.
Another interesting rumor concerns AMD's Vega 20 series. DigiTimes claims AMD will likely switch orders to TSMC to produce these chip at 7nm FinFET process and with TSMC's CoWoS packaging. Not a lot of details are available about Vega 20 but the site hints it may primarily be aimed at supercomputers. Perhaps Vega 20 will be a compute-heavy architecture like NVIDIA's GV100, this implies Navi may be the Vega 10 successor in the consumer lineups.