If the true odds increase the bet has a negative value. This happens from time to time and is completely normal. Only something like 80 to 90% of bets beat the closing line. This is still enough to make a profit. Remember that odds can also move the other way meaning your value can also increase after you placed the bet.
There is a lot of talk about the time to match start but Rebelbetting statistics show that it has little to no correlation to results. Check the original topic.