It is unlikely, but it is possible. There are multiple reasons why this might be the case. The most common is that due to network delay, or drive speed delay (for example using a slow NAS), you missed the time for inclusion into the blockchain, which is 28 seconds. This time is from when the timelords create the signage points, to when the timelords infuse your block. Check to make sure that you are connected and synced to multiple peers, and that your quality lookup are fast (<2 seconds, definitely less than 5). Another reason might be that the signage point where you won did not get included into the blockchain. This can sometimes happen, since timelords may publish signage points that don't end up on chain.
