In the God of Destruction Beerus saga of Dragon Ball Super we see Goku heals from a mortal wound made by Beerus when transformed in Super Saiyan God. But in the Golden Freezer saga we see Goku being wounded to death by Freezer when fighting in Super Saiyan Blue. He does nothing to recover himself when he could have used the Super Saiyan God transformation to heal himself.
Why didn't Goku use Super Saiyan God's regenerative abilities to recover from Freezer's deathly blow?
The most likely explanation is that it's just a contradiction introduced by Toei Animation.
While Toriyama writes the general plot of Dragon Ball Super, both Toei Animation and Toyotaro are free, to some extent, to fill the holes left by Toriyama. These additions usually contradict future events when they mess with not-well-defined concepts (e.g. the scope of Super Saiyan God's powers) and Toriyama later starts defining them (e.g. by showing that such transformation cannot in fact heal).
In this case, Goku's mortal wound made by Freeza was probably Toriyama's idea while the one made by Beerus was added by Toei Animation without considering future implications.
It could also be that Toriyama himself introduced this plot hole, but the scenario I described above happens more often.
