Sounds like my wide-screen scenes proving too much for my now-ageing twin GPU cards' 'vols & buckets' settings. For 'not-too-complex' scenes, 1024 suits. When complexity grows, must progressively binary-chop down through 256 to 64, which is what suits a 'CPU-only' render, either on this PC or my networked 'Box'...

I cannot reproduce it, but I sometimes feel that leaving P_11 'open' for a day or two with a complex scene may lead to instability.

IMHO, Poser could do with an 'Engineering' display, showing gas gauge, oil-pressure etc...