win32/1.8.4 newlines inconsistent in Query window's Messages pane

Whenever I have a standard 'raise notice' in one of my functions for
debugging, and I run a select statement on the function in the query,
the Messages pane only sometimes puts newlines after "NOTICE: ..."
lines, and if I just keep hitting F5, it's after different lines every
time. Often there are many lines in a row with newlines, and often
there are many in a row that are bunched together without newlines:

NOTICE: test
NOTICE: test
NOTICE: test
NOTICE: test
NOTICE: test
NOTICE: testNOTICE: testNOTICE: testNOTICE: testNOTICE: test
NOTICE: testNOTICE: test
Total query runtime: 344 ms.
1 rows retrieved.

NOTICE: test
NOTICE: test
NOTICE: test
NOTICE: testNOTICE: testNOTICE: test
NOTICE: testNOTICE: testNOTICE: testNOTICE: test
NOTICE: testNOTICE: test
Total query runtime: 453 ms.
1 rows retrieved.

If I do this in psql, all newlines come out correctly, one after each
"NOTICE" line.