Old SP2 scene bugged with Building Light cache

HELLO,
we have few times a week this problem, which is almost sure a bug, is there a way to by pass it ? The only way we can work over is to change the light cache for a brut force for example. It appears all the time we work on an old scene SP2 with the SP3 and we merged into this scene new object did with the SP3 from scratch.
The Building Light Cache never end…

Tanguy

See below the message: