Solar duties applied retroactively

Hi,

Is it common that such high duties can be applied retroactively?

https://pv-magazine-usa.com/2025/08/26/trade-court-affirms-solar-duties-under-biden-moratorium/

For me it seems very weird, as the Biden Admin waived the duties and companies acted accordingly. For some, this might lead to billion in damages.

How likely would an appeal be?

Thanks!