I wouldn't be surprised at all if that has happened. When you run a running event, you get one shot at it and one of the major limiting factors is the energy in your body. It isn't that technique doesn't matter, but if a runner ran a subpar race and was then offered another opportunity to try again a few minutes later, that runner probably isn't going to be faster.
On the other hand, field eventers are accustomed to having multiple attempts and their first attempt is not always their best. Mechanics play such a huge role that the athlete sometimes needs to find his or her groove. In field events, the number of attempts is a limiting factor. In practice, there is no such limit. A shot putter probably won't throw that well if he or she is taking 50 attempts in practice, but if he or she gets to take 10 warm-up tosses and then throw for real 10 times (not what would happen every single day), I could see that happening.
I am a high school coach so I'm not overseeing world record quality performances, but the amount of times I've had to explain to field event athletes that I can't count their practice marks on different lists absolutely numbers in the hundreds by now. Some of those marks that I am talking about are coming from some very good athletes, not just beginners who PR every time they step in the ring/on the runway.