henningw left a comment (kamailio/kamailio#4250)
@miconda Its more a bug fix, similar as we have done e.g. in faca8e7a20255d90 and ccc1069228
The tm module documentation clearly states that it should work for all locally generated requests: "Executed when the tm module generates a request, in other words, the request originates from Kamailio and a transaction is created for it. The source of the requests can be tm itself or other modules that use tm internally (e.g., msilo, uac)."
I don't think we need to add a module parameter for it, documenting it clearly in the migration guide should be fine.