It is worth noting that this was claimed in exactly one publication from researchers that are not experts in the field. The publication has meanwhile earned an expression of concern [1] by the publisher that unfortunately does not give much more details. It is also quite strange that the paper was published in a journal about cancer research.
The other big inconsistency is that the epidemic did not become nonticeable in Italy until late February 2020. If COVID was already present in September 2019, why didn't it spread rapidly like it did anywhere else?
[1] https://journals.sagepub.com/doi/full/10.1177/03008916209877...