Hello Peter, *, would you be so kind to give us a step by step instruction, please? I am not sure, what you want us to tell with your "At first mailmerge access...", sorry ... :( Have a nice evening Thomas.
No feedback after 6 months, let's close this one. Peter: don't hesitate to reopen this tracker if you still reproduce this with last stable LO version (5.2.4). In this case, please provide some extra information requested by previous comment https://bugs.documentfoundation.org/show_bug.cgi?id=100511#c1