I have heard of the concept of a "cula-sotapanna" ("lesser" sotapanna), as discussed here for example: viewtopic.php?f=13&t=434
It seems to designate a person who is not yet a sotapanna but for some reason will definitely attain the fruit of sotapatti upon death, or even shortly thereafter, after being reborn in some deva realm where he swiftly receives instruction.
So that's something different than what you were talking about.
I also remember vaguely someone (I think it might have been Bhante Yuttadhammo in one of his gazillions of videos) talking about some "attainment" where a person has been able to see the workings of kamma clearly, so that they are unable to do anything in this life which will take them to one of the lower realms, but they have not yet abandoned the three lower fetters and can forget about what they saw in the next life, and so go down again. I think that was also referred to as cula-sotapanna, so maybe the term is not quite so definitely defined and agreed upon. But I have not investigated this very much.
But what you mention about someone being unable to go to the lower realms ever anymore, but not being a stream-enterer, or on his definite way to stream-entry, is something I have never heard of.