Epoxy seals can be hydroscopic or absorb molecules of H2O
Each Mfg and part has a Class rating for these,
In the old days plastic parts were never rated below 0'C , hence consumer spec is to prevent ice cracking wirebonds. This problem was cured by Sumitomo, I believe.
LEDs use a different "water-clear" Epoxy which is more hydroscopic and lower glass transition temp.
The other issue is humidity absorption to prevent pop-corn effect with solder profile temps. which can shear the extremely thin gold-wire bonds, ( not explode the part) Nothing worse than a part fail for no connection in the field, en mass. A qualified process/quality engineer ought to be able to judge the corrective action.with traceability on part info.
The routine task for unsealed parts exceeding mfg shelf life for moisture is to bake the parts to remove moisture prior to soldering as per IPC std.