Has someone ever studied this phenomenon? I don't mean my specific example, but like, in general.
I know it has been studied within a language community. For example, there have been studies on the saliency of VOT in the perception of voiced plosives in English, or aspirated plosives in Cypriot Greek (and afaik, in both cases, duration came out being more salient than VOT).
So I think the same methodology can apply to your question about L2 representations of vowels.
What you have to make sure though is that you know exactly what vowel the Italian speakers are trying to transfer.
I'm saying that, because there's a consistent pattern of Greece Greek speakers transferring English /ʌ/ as [ɔ] (and /æ/ as [ε]), while Cypriot Greek speakers like myself, transfer /ʌ/ as [ɐ] (/æ/ also becomes [ɐ]).
So, while it could be that we we use a different sound feature to transfer the English vowels, there's a catch. My phonetics professor said to me, when I came up with a similar question, that in Cyprus we are more exposed to varieties of English that have a centralised /ʌ/ and a lower /æ/, but Greeks aren't. Their L2 education etc targets American English instead, so they are actually transferring different vowels than we do.