Andrew,
In April 2020, 240,000 Silver Eagles were minted in Philadelphia while operations were temporarily suspended at the West Point Mint due to the coronavirus pandemic, making this the second rarest bullion issue Silver Eagle in the series' 34 year history.
With a mintage of only 240,000, the 2020 Philadelphia Silver Eagle is among the rarest bullion issue Silver Eagles, second only to the 2015 Philadelphia issue.
Silver Eagles were produced at the Philadelphia Mint between April 8th and April 20th, 2020, as a result of the impact of the coronavirus pandemic on operations at the West Point Mint, where Silver Eagles are typically produced. This marks the first time since 2017 that Silver Eagles were made outside of West Point, and the second smallest production of bullion Silver Eagles since 1986. With a mintage of only 240,000, these Silver Eagles are among the rarest Silver Eagles available, with less than 7% of the mintage of the key date 1996 coin.
With respect to PCGS graded coins for 2020-P Emergency Issue, there were First Strike, First Day of Issue, and Early Release...NGC looks to be similar with the 2020 (P) Emergency Production. I am sure there is some distinction between those three strike nuances over 13 days of mintage, but I am typically dumbfounded by what that may be.