Vafa Khalighi wrote:

having

$$1+2=3\eqno(1)$$ $$1+2=3\eqno(1)$$ $$1+2=3\eqno(1)$$

\end

as the example document and running pdftex and luatex on it, it makes clear that with space between equations is too much when compiled with luatex. both PDFTeX and LuaTeX outputs are attached.

Hi Taco and others

Can you or anyone else suggest a workaround for this bug please (except \vskip -\baselineskip or something to do with \everypar)?

\everydisplay{\vskip -\baselineskip} maybe. This bug is on the short list to be fixed in the next beta, but I have not had time to actually look at it yet. Best wishes, Taco