No it was not, I was using a solid object so I left it at onesided. I understand that some thresholds could cause some leaks in hdcache, however it still looks weird cause it was either going through and was refining progressively or it did not get through at all and was not appearing after a while so I was just thinking it might be a bug or somethin. I thought that maybe corona was having problems with the geometry of glass having edges at the same place as walls so I've made the glass object significantly smaller and again, I press render the spot from area is there, stop press again, it's gone... again and it's there.. I need to build some simple test scene to get to know what's all the settings in hdcache about, cause it looks i'm missing something quite important there :D....