Despite it not being a perfect match for Elaeagnus umbellata, I think you have enough characteristics to place it in the Elaeagnus genus.

If you look on the USDA Plants database, there is a subform, and I'm sure there are others due to hybridization.

And of course invasive plants like these can seed around a bit (I pick out seedlings from my neighbor's elaeagnus all the time) and become "naturalized" ((shutter)).

Here is a link that might be useful: Elaeagnus umbellata Thunb. var. parvifolia

I think it is most likely just a local variant of E. umbellata. It is not at all unusual to find quite a lot of variation within any species of plant.

I also have this plant in the field behind my house and would love to know what it is. Very fragrant tiny tube shaped flowers. There are also plenty of volunteer eleagnus in the same field. They bloom in a different time of the year (seems like fall or winter) from this unidentified one.

Elaeagnus umbellata

pretty sure it is a local E. umbellata. I have one too. i think eleagnus must be one of those plants like hawthorn that will hybridize indefinitely.