The only one I found a time series for quickly is Lamb Weston: Their margins steadily went down after 2019, then surged quite substantially, and by the end of 2024 were more or less back at their 21/22 low points [1]
Additionally there's apparently a class action suit against the companies mentioned which was filed in November 2024 [2]
I don't know enough about this market to judge whether something shady happened, but it seems like both of those facts are relevant to this article.
1. https://www.macrotrends.net/stocks/charts/LW/lamb-weston/pro...
2. https://www.hbsslaw.com/cases/frozen-potato-products-antitru...