groff ms writer: Formatting below math formula

[rlefmann]

When creating groff ms output, the text following a math formula is not formatted correctly. Example:

This is some text, followed by an equation
$$
a^2 + b^2 = c^2
$$
and some more text.

pandoc input.md -s -t ms -o output.pdf

The text following the math formula completely disappears in the output. If I add an empty line after the equation, the text is formatted in a new (indented) paragraph.

The problem is most likely a missing newline in the output (following the .EN macro):

...
This is some text, followed by an equation
.EQ
a sup 2 + b sup 2 = c sup 2
.EN and some more text.
...

If I add the newline in the ms output file and then run

eqn output.ms -T pdf | groff -ms -T pdf > output.pdf

the output pdf is formatted as expected.