The argument OpenTofu and their lawyers are making is that they didn’t copy the “removed” statement, which is under the new BUSL license, they looked at the “moved” statement (licensed originally under MPL) and derived their own removed statement from that. Maybe true but I can’t help but wonder if there was any “parallel construction” involved.

If you look at the PR in OpenTofu: https://github.com/opentofu/opentofu/pull/1158

It claims to fix this issue: https://github.com/opentofu/opentofu/issues/1032

Which in turn references this issue in terraform: https://github.com/hashicorp/terraform/issues/34402

I’m not a lawyer and have no idea who is right or wrong but I understand why Hashicorp is scrutinizing this.