jabref can't parse bib file when the bibtexkey field contains symbol "="

[Moriaty0o0]

JabRef 5.1--2020-06-15--ed96faa
Windows 10 10.0 amd64
Java 14.0.1

• Mandatory: I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

jabref can't parse bib file when the bibtexkey field contains symbol =.
the error information :
error occurred when parsing entry: 'error in line 1626: expected = but received , '. Skipped entry.

for some reason , i can't show the complete bib entry, but i‘m sure it is the bibtexkey contains symbol "=" that make error occur.

the title of the entry contains equal sign "=" and i make bibtexkey consists of title, so error occurs.

Log File

%d [%thread] %-5level %logger - %msg%nImporting in unknown format: game.bib Error opening file 'game.bib': Could not find a suitable import format.

[Siedlerchr]

The equal sign is illegal in the key. Therefore JabRef is right that the entry is invalid.