Where is that from, is it your board? That is not good. If there are ANY traces or components under the board it is not acceptable.
It certainly looks heat damaged, and if it is then it is a long term threat. The board is conducting heat and this process will continue.
As FR4 contiunes to conduct heat a limit is reached, where it cannot conduct any more heat, and this will cause the warping. The warped area will see a decline in it's abiltity to disipate heat (which is good but not that good in the first place) This also alters the environmental characteristics of the board. You can no longer guarantee any environmental spec on the board (heat, vibration, cooling, etc.). It is potentially possible that traces and components will be damaged as a result of the spreading. If that much heat is failing to be dissipated from the board then nearby components will also be suffering. The trouble is that it might take a few years, and in that case the board will be obsolete before it actually causes damage, and therefore no support is necessary.
It is bad design. However it depends on who placed the heatsink, and whether or not the enclosure met the specs. Not enough information to state who is responsible. But it is not acceptable - whoever claimed that does not know what they are talking about, or they based their decision on the fact that the board will be obsolete before more serious damage can occur.
