In both situations you were coasting right? I'd go for the cold being a contributing factor the [MENTION=197614]fietsbob[/MENTION] mentioned. The speed may have had something to do with why it did one time and not the other.

Did you just indiscriminately put oil wherever you think it needed it?

If so, and it got down into the freehub or freewheel, then it may have been too much lube or too much viscosity for it. It might take care of itself after a few rides or you can try to squirt a lighter lube in there.

So is it a freewheel or freehub? What did you oil it with?