SvTYPE() merely tells you the type of the storage container; it doesn't in general say what the logical type of the SV is.

Since 5.12.0, the SVt_RV sv type has been abolished, on the grounds that the SVt_IV container type is perfectly capable of holding a reference.

In general you shouldn't be basing code on tests like SvTYPE(sv) == SVt_RV; instead you should be testing the relevant flags, e.g.:

if (SvROK(sv))
    ref = SvRV(sv);
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Dave.