Fixed a rather gnarly bug in @fedify last night where schema.org's @context wasn't being resolved correctly because schema.org doesn't do content-neg and instead using link alternate headers to point to the JSON-LD context document. However, instead of using a fully qualified URL, it used a relative URL to the initial request, which caused Fedify to fail to fetch that context.
This would propagate through @fedify to implementations (e.g., Hollo) where they would fail to lookup the @context for schema.org, which would prevent fetching Actor documents from GoToSocial 0.19.x
cc @gotosocial in case this is something you want to improve on your side