invalid lightmap samples

hi all,
maybe this is a stupid question, i don’t know..
but how come i often get a message like “invalid lightmap samples”
i’m having irrmap/lightcache, and the lightcache is like 1000 over 0,02 just default. is there any factor causing this particular problem?

thanks

I’ve got these warnings quite often. If you don’t see any stange splotches or excessive rendertime, don’t worry too much about it.