https://www.guru3d.com/news-story/amd-roadmaps-mention-rdna2zen3-and-zen4.html
 
AMD updated its technology roadmaps to reflect a 2020 launch window for its upcoming CPU and graphics architectures, "Zen 3" and RDNA2. The two will be based on 7 nm+ , which is AMD-speak for the 7 nanometer EUV silicon fabrication process at TSMC, that promises a significant 20 percent increase in transistor-densities, giving AMD high transistor budgets and more clock-speed headroom. The roadmap slides however hint that unlike the "Zen 2" and RDNA simultaneous launch on 7th July 2019, the next-generation launches may not be simultaneous.
 
The slide for CPU microarchitecture states that the design phase of "Zen 3" is complete, and that the microarchitecture team has already moved on to develop "Zen 4." This means AMD is now developing products that implement "Zen 3." On the other hand, RDNA2 is still in design phase. The crude x-axis on both slides that denotes year of expected shipping, too appears to suggest that "Zen 3" based products will precede RDNA2 based ones. "Zen 3" will be AMD's first response to Intel's "Comet Lake-S" or even "Ice Lake-S," if the latter comes to fruition before Computex 2020. In the run up to RDNA2, AMD will scale up RDNA a notch larger with the "Navi 12" silicon to compete with graphics cards based on NVIDIA's "TU104" silicon. "Zen 2" will receive product stack additions in the form of a new 16-core Ryzen 9-series chip later this month, and the 3rd generation Ryzen Threadripper family.
 

 
 
 

I would think that, since AMD is a close customer of TSMC, AMD would have had that discussion with TSMC prior to planning its roadmap. It's not like TSMC would all of the sudden realize 2 days later that it needed to delay schedules en mass.