...that keeps liquid hide glue liquid in the bottle can keep it plastic before fully drying, especially if it's not thinly spread. As George Wilson and Dave Anderson have noted, warming helps in this respect.
Because of these and other issues, I rarely use LHG for pieces where it's a clear advantage to do so, opting for HHG in most cases—even for very small glue-ups where I just microwave a tiny bit with minimal waste. I've never used up a whole bottle of LHG before it's gone iffy. Besides, I'm impatient.