I started an extra instance of BOINC to save other project results from uploading for two days for a short race. I added GCC and later, after the race, your project at about the same time I added Sztaki (I can get Sztaki WUs if no other CPU intensive projects are running!). It took more than a day to get Sztaki WUs and now WUProp is only giving invalid results and nothing for a couple days running Sztaki.

Is there a solution to getting Sztaki recorded?

For me at least, tasks from that project are sporadic. If your client is not running anything but NCI apps like GCC then they will all be returned as Invalid. See this thread:
http://wuprop.boinc-af.org/forum_thread.php?id=441