Serial letters under LO 5

Hello,
Having been a LibreOffice enthusiast for years I thought I'd try out LO 5.1.0 RC2.
I find I have the following problem:
When selecting more than one row from my MySQL-Database to print serial letters,
only the first of them gets selected und printed. This happens also on LO 5.0.
Doing the same on 4.4.7, everything works just fine. Has anybody experienced the
same issue?
My systems are Linux-Debian 8, Linux-Mint 17.2 (both using KDE), and Windows 7.
The connection to the database is through JDBC in all cases. I think this issue
should be solved before LO 5.1 is finally made available to the public.
Regards (from snowed-in Salzburg)
H. Stoellinger