When using the "+" symbol to add fields, stray fields may be left and shouldn't be a part of the transaction.
an example with a stray field:
[
{":db/id" #db/id [":db.part/db"]
":db/ident" ":myname/enum1"}
{":db/id" #db/id [":db.part/db"]
":db/ident" ":myname/enum2"}
{":db/id" #db/id [":db.part/db"]
":db/ident" ":myname/null"}
]