Hi,
JabRef 5.2--2020-12-24--6a2a512
Windows 10 10.0 amd64
Java 14.0.2

When importing a bibTex citation from a publisher, uppercase abbreviations of editors names is often protected with curly braces, like that:
{IEEE} Journal of Quantum Electronics

If the journal abbrevations list contains the unprotected version:
IEEE Journal of Quantum Electronics

Jabref does not recognize the journal name.

Suggestion: remove curly braces before searching for an abbrevation