This bug (title is self-explanatory) appeared after Marius' commits of December 18, and was already reported on the chessx-developer mailing list together with the other bug "any game has twice the first move". Since the latter is now fixed, i hope also this one will be gone soon. :)
A patch is available, i am going to test it.
After commit 892 with the patch of Alessandro Gandelli the bug is gone. Please note that bug #1722338 (Comments before the first move are not shown) still stands.