I think this is the Italian study you reference: https://journals.sagepub.com/doi/full/10.1177/03008916209747...

Again, they didn't (or failed to) sequence the virus to prove it was in the samples, and their antibody data (fig 1) doesn't make any sense. IgM antibodies are acute and IgG longer-lasting, so they should appear more like a cumulative distribution if there was a real outbreak. They didn't test their antibody assay for cross-reactivity to seasonal coronaviruses, so that's probably what's going on here.

Same story for the American study (https://academic.oup.com/cid/advance-article/doi/10.1093/cid...), though Forbes was at least minimally competent enough to quote a scientist's tweet pointing out the limitations, and the authors even address "potential cross reactivity with human common coronavirus infection". Only 1 sample, from 10 Jan 2020, was positive across all their antibody tests, and no samples were sequenced! These studies all fail to properly account for the false positive rate of their assays, and then pretend that all the positive hits are SARS-CoV-2 without any orthogonal verification.